diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 96dbd9e1d..f2847c405 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -18,6 +18,7 @@ permissions: { }
 
 jobs:
   crate-build:
+    if: ${{ needs.generate-matrix.outputs.any_builds == 'true' }}
     needs:
       - generate-matrix
     runs-on: ${{ matrix.runner }}
@@ -114,6 +115,7 @@ jobs:
           STEPS_GET_LABELS_OUTPUTS_LABELS: ${{ steps.get-labels.outputs.labels }}
 
   build:
+    if: ${{ needs.generate-matrix.outputs.any_builds == 'true' }}
     timeout-minutes: 90
     needs:
       - generate-matrix
diff --git a/cpython-unix/build-cpython.sh b/cpython-unix/build-cpython.sh
index 8dd0240b8..35009efa7 100755
--- a/cpython-unix/build-cpython.sh
+++ b/cpython-unix/build-cpython.sh
@@ -82,6 +82,12 @@ rm Lib/ensurepip/_bundled/pip-*.whl
 cp "${PIP_WHEEL}" Lib/ensurepip/_bundled/
 sed "${sed_args[@]}" "s/^_PIP_VERSION = .*/_PIP_VERSION = \"${PIP_VERSION}\"/" Lib/ensurepip/__init__.py
 
+# Build relative runtime library paths into CPython 3.15+.
+if [ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_15}" ]; then
+    patch -p1 -i "${ROOT}/patch-relocatable-flag.patch"
+    patch -p1 -i "${ROOT}/patch-relocatable-link.patch"
+fi
+
 # configure doesn't support cross-compiling on Apple. Teach it.
 if [[ "${PYBUILD_PLATFORM}" = macos* && -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_13}" ]]; then
     if [ "${PYTHON_MAJMIN_VERSION}" = "3.12" ]; then
@@ -152,7 +158,9 @@ fi
 
 # The default build rule for the macOS dylib doesn't pick up libraries
 # from modules / makesetup. So patch it accordingly.
-if [ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_13}" ]; then
+if [ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_15}" ]; then
+    patch -p1 -i "${ROOT}/patch-macos-link-extension-modules-15.patch"
+elif [ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_13}" ]; then
     patch -p1 -i "${ROOT}/patch-macos-link-extension-modules-13.patch"
 else
     patch -p1 -i "${ROOT}/patch-macos-link-extension-modules.patch"
@@ -333,6 +341,10 @@ fi
 
 EXTRA_CONFIGURE_FLAGS=
 
+if [ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_15}" ]; then
+    EXTRA_CONFIGURE_FLAGS="${EXTRA_CONFIGURE_FLAGS} --enable-relocatable"
+fi
+
 if [[ "${PYBUILD_PLATFORM}" = macos* ]]; then
     CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include/uuid"
 
@@ -818,18 +830,22 @@ if [ "${PYBUILD_SHARED}" = "1" ]; then
 
         # Fix the Python binary to reference libpython via @rpath and add
         # an rpath entry so it can find the library.
-        install_name_tool \
-            -change "/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" "@rpath/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" \
-            -add_rpath @executable_path/../lib \
-            "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}"
+        if [ -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]; then
+            install_name_tool \
+                -change "/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" "@rpath/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" \
+                -add_rpath @executable_path/../lib \
+                "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}"
+        fi
 
         # Python's build system doesn't make this file writable.
         chmod 755 "${ROOT}/out/python/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}"
         # Set libpython's install name to @rpath so binaries linking against it
         # can locate it via their own rpath entries.
-        install_name_tool \
-            -id "@rpath/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" \
-            "${ROOT}/out/python/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}"
+        if [ -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]; then
+            install_name_tool \
+                -id "@rpath/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" \
+                "${ROOT}/out/python/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}"
+        fi
 
         # We also normalize /tools/deps/lib/libz.1.dylib to the system location.
         install_name_tool \
@@ -839,19 +855,19 @@ if [ "${PYBUILD_SHARED}" = "1" ]; then
             -change /tools/deps/lib/libz.1.dylib /usr/lib/libz.1.dylib \
             "${ROOT}/out/python/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}"
 
-        if [ -n "${PYTHON_BINARY_SUFFIX}" ]; then
+        if [[ -n "${PYTHON_BINARY_SUFFIX}" && -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]]; then
             install_name_tool \
                 -change "/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" "@rpath/${LIBPYTHON_SHARED_LIBRARY_BASENAME}" \
                 -add_rpath @executable_path/../lib \
                 "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}${PYTHON_BINARY_SUFFIX}"
         fi
 
-        # At the moment, python3 and libpython don't have shared-library
-        # dependencies, but at some point we will want to run this for
-        # them too.
-        for module in ${ROOT}/out/python/install/lib/python*/lib-dynload/*.so; do
-            install_name_tool -add_rpath @loader_path/../.. "$module"
-        done
+        # The relocatable backport supplies extension search paths for CPython 3.15+.
+        if [ -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]; then
+            for module in ${ROOT}/out/python/install/lib/python*/lib-dynload/*.so; do
+                install_name_tool -add_rpath @loader_path/../.. "$module"
+            done
+        fi
     else # (not macos)
         LIBPYTHON_SHARED_LIBRARY_BASENAME=libpython${PYTHON_MAJMIN_VERSION}${PYTHON_BINARY_SUFFIX}.so.1.0
         LIBPYTHON_SHARED_LIBRARY=${ROOT}/out/python/install/lib/${LIBPYTHON_SHARED_LIBRARY_BASENAME}
@@ -917,12 +933,14 @@ if [ "${PYBUILD_SHARED}" = "1" ]; then
         # empty dummy libpython.so, which allows the link to succeed but
         # ensures they do not use any unwanted symbols. That might be
         # worth doing at some point.)
-        patchelf --force-rpath --set-rpath "\$ORIGIN/../lib" \
-            "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}"
-
-        if [ -n "${PYTHON_BINARY_SUFFIX}" ]; then
+        if [ -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]; then
             patchelf --force-rpath --set-rpath "\$ORIGIN/../lib" \
-                "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}${PYTHON_BINARY_SUFFIX}"
+                "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}"
+
+            if [ -n "${PYTHON_BINARY_SUFFIX}" ]; then
+                patchelf --force-rpath --set-rpath "\$ORIGIN/../lib" \
+                    "${ROOT}/out/python/install/bin/python${PYTHON_MAJMIN_VERSION}${PYTHON_BINARY_SUFFIX}"
+            fi
         fi
 
         # For libpython3.so (the ABI3 library for embedders), we do
@@ -941,8 +959,9 @@ if [ "${PYBUILD_SHARED}" = "1" ]; then
         # libpython3.x.so.1.0 that they want (and it's fine to use
         # DT_RUNPATH instead of DT_RPATH).
         if [ "${CC}" == "musl-clang" ]; then
-            # libpython3.so isn't present in debug builds.
-            if [ -z "${CPYTHON_DEBUG}" ]; then
+            # The relocatable backport supplies this path for CPython 3.15+.
+            # libpython3.so is absent from debug builds.
+            if [[ -z "${CPYTHON_DEBUG}" && -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]]; then
                 patchelf --set-rpath "\$ORIGIN/../lib" \
                     "${ROOT}/out/python/install/lib/libpython3.so"
             fi
@@ -956,9 +975,11 @@ if [ "${PYBUILD_SHARED}" = "1" ]; then
 
         # Let _tkinter locate bundled Tcl/Tk libraries independently of the
         # interpreter.
-        for module in "${ROOT}"/out/python/install/lib/python*/lib-dynload/_tkinter*.so; do
-            patchelf --force-rpath --set-rpath "\$ORIGIN/../.." "$module"
-        done
+        if [ -n "${PYTHON_MEETS_MAXIMUM_VERSION_3_14}" ]; then
+            for module in "${ROOT}"/out/python/install/lib/python*/lib-dynload/_tkinter*.so; do
+                patchelf --force-rpath --set-rpath "\$ORIGIN/../.." "$module"
+            done
+        fi
     fi
 fi
 
diff --git a/cpython-unix/patch-macos-link-extension-modules-15.patch b/cpython-unix/patch-macos-link-extension-modules-15.patch
new file mode 100644
index 000000000..70993e9a6
--- /dev/null
+++ b/cpython-unix/patch-macos-link-extension-modules-15.patch
@@ -0,0 +1,20 @@
+--- a/Makefile.pre.in
++++ b/Makefile.pre.in
+@@ -1053,7 +1053,7 @@
+ 	$(BLDSHARED) $(NO_AS_NEEDED) -o $@ -Wl,-h$@ $^
+ 
+ libpython$(LDVERSION).dylib: $(LIBRARY_OBJS)
+-	 $(CC) -dynamiclib $(PY_CORE_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(prefix)/lib/libpython$(LDVERSION).dylib -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(SHLIBS) $(LIBC) $(LIBM); \
++	 $(CC) -dynamiclib $(PY_CORE_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(prefix)/lib/libpython$(LDVERSION).dylib -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(MODLIBS) $(SHLIBS) $(LIBC) $(LIBM); \
+ 
+ 
+ $(RELOCATABLE_DIR)/libpython$(LDVERSION).so: $(LIBRARY_OBJS) $(DTRACE_OBJS)
+@@ -1066,7 +1066,7 @@
+ 
+ $(RELOCATABLE_DIR)/libpython$(LDVERSION).dylib: $(LIBRARY_OBJS)
+ 	@mkdir -p $(@D)
+-	$(CC) -dynamiclib $(PY_CORE_LDFLAGS) $(RELOCATABLE_LIBPYTHON_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(RELOCATABLE_LIBPYTHON_INSTALL_NAME) -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(SHLIBS) $(LIBC) $(LIBM)
++	$(CC) -dynamiclib $(PY_CORE_LDFLAGS) $(RELOCATABLE_LIBPYTHON_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(RELOCATABLE_LIBPYTHON_INSTALL_NAME) -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(MODLIBS) $(SHLIBS) $(LIBC) $(LIBM)
+ 
+ libpython$(VERSION).sl: $(LIBRARY_OBJS)
+ 	$(LDSHARED) -o $@ $(LIBRARY_OBJS) $(MODLIBS) $(SHLIBS) $(LIBC) $(LIBM)
diff --git a/cpython-unix/patch-relocatable-flag.patch b/cpython-unix/patch-relocatable-flag.patch
new file mode 100644
index 000000000..4e8b54f8e
--- /dev/null
+++ b/cpython-unix/patch-relocatable-flag.patch
@@ -0,0 +1,74 @@
+diff --git a/Doc/using/configure.rst b/Doc/using/configure.rst
+index 0d420d8..2cc8e94 100644
+--- a/Doc/using/configure.rst
++++ b/Doc/using/configure.rst
+@@ -1073,6 +1073,17 @@ Linker options
+ 
+    Enable building a shared Python library: ``libpython`` (default is no).
+ 
++.. option:: --enable-relocatable
++
++   Enable experimental support for relocatable builds (default is no).
++   This option currently has no effect on the build.
++
++   .. warning::
++
++      This feature is under active development. Do not use it in production.
++
++   .. versionadded:: 3.16
++
+ .. option:: --without-static-libpython
+ 
+    Do not build ``libpythonMAJOR.MINOR.a`` and do not install ``python.o``
+diff --git a/Makefile.pre.in b/Makefile.pre.in
+index 36515db..7dcfc45 100644
+--- a/Makefile.pre.in
++++ b/Makefile.pre.in
+@@ -60,6 +60,7 @@ DSYMUTIL=       @DSYMUTIL@
+ DSYMUTIL_PATH=  @DSYMUTIL_PATH@
+ 
+ GNULD=		@GNULD@
++RELOCATABLE=	@RELOCATABLE@
+ 
+ # Shell used by make (some versions default to the login shell, which is bad)
+ SHELL=		/bin/sh -e
+diff --git a/configure.ac b/configure.ac
+index a8760c9..1afbeba 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -1594,6 +1594,21 @@ if test "x$enable_profiling" = xyes; then
+   LDFLAGS="-pg $LDFLAGS"
+ fi
+ 
++AC_MSG_CHECKING([for --enable-relocatable])
++AC_ARG_ENABLE([relocatable],
++  AS_HELP_STRING([--enable-relocatable],
++                 [enable experimental relocatable build support (default is no)]),
++  [], [enable_relocatable=no])
++AS_CASE([$enable_relocatable],
++  [yes|no], [],
++  [AC_MSG_ERROR([--enable-relocatable must be yes or no])])
++AC_MSG_RESULT([$enable_relocatable])
++AS_VAR_IF([enable_relocatable], [yes], [
++  AC_DEFINE([Py_ENABLE_RELOCATABLE], [1],
++            [Define if --enable-relocatable is used.])
++])
++AC_SUBST([RELOCATABLE], [$enable_relocatable])
++
+ AC_MSG_CHECKING([LDLIBRARY])
+ 
+ # Apple framework builds need more magic. LDLIBRARY is the dynamic
+diff --git a/pyconfig.h.in b/pyconfig.h.in
+index 08306a1..4fb029a 100644
+--- a/pyconfig.h.in
++++ b/pyconfig.h.in
+@@ -1880,6 +1880,9 @@
+ /* Define if you want to build an interpreter with many run-time checks. */
+ #undef Py_DEBUG
+ 
++/* Define if --enable-relocatable is used. */
++#undef Py_ENABLE_RELOCATABLE
++
+ /* Defined if Python is built as a shared library. */
+ #undef Py_ENABLE_SHARED
+ 
diff --git a/cpython-unix/patch-relocatable-link.patch b/cpython-unix/patch-relocatable-link.patch
new file mode 100644
index 000000000..adfc13504
--- /dev/null
+++ b/cpython-unix/patch-relocatable-link.patch
@@ -0,0 +1,337 @@
+diff --git a/Doc/using/configure.rst b/Doc/using/configure.rst
+index 2cc8e94..203b04e 100644
+--- a/Doc/using/configure.rst
++++ b/Doc/using/configure.rst
+@@ -1076,12 +1076,31 @@ Linker options
+ .. option:: --enable-relocatable
+ 
+    Enable experimental support for relocatable builds (default is no).
+-   This option currently has no effect on the build.
+ 
+    .. warning::
+ 
+       This feature is under active development. Do not use it in production.
+ 
++   Currently, this sets relative runtime library paths on Linux and for
++   non-framework macOS builds. Framework relocation is not implemented yet.
++   Combining this option with :option:`--enable-framework` is an error.
++
++   Move the installation as a unit. It must use the default ``bin`` and ``lib``
++   directories under a common prefix. :option:`--with-platlibdir` may select
++   a different directory name for the standard library, but not a nested path.
++   On Linux, these paths use ``DT_RPATH``.
++
++   Copied virtual environments from non-framework shared builds require
++   directory symlinks to the base installation's libraries. Virtual environments
++   depend on their base installation and must be recreated if it moves.
++
++   Dependencies stored in other directories, such as ``lib/tcltk``, may
++   need additional loader search paths.
++
++   This option does not bundle dependencies, adjust data-file lookup for
++   libraries such as Tcl/Tk, or rewrite script shebangs and build-time
++   paths in :mod:`sysconfig`.
++
+    .. versionadded:: 3.16
+ 
+ .. option:: --without-static-libpython
+diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
+index c74ca05..791dc53 100644
+--- a/Lib/test/test_sys.py
++++ b/Lib/test/test_sys.py
+@@ -2372,9 +2372,11 @@ def test_remote_exec_deleted_libpython(self):
+                 os.symlink(instsoname, os.path.join(lib_dir, ldlibrary))
+ 
+             env = os.environ.copy()
+-            ld_library_path = env.get('LD_LIBRARY_PATH')
+-            env['LD_LIBRARY_PATH'] = lib_dir if not ld_library_path else (
+-                lib_dir + os.pathsep + ld_library_path)
++            # Preload the copy even when the interpreter's RPATH takes
++            # precedence over LD_LIBRARY_PATH.
++            ld_preload = env.get('LD_PRELOAD')
++            env['LD_PRELOAD'] = copied_libpython if not ld_preload else (
++                copied_libpython + os.pathsep + ld_preload)
+ 
+             self._run_remote_exec_with_deleted_mapping(copied_libpython,
+                                                        env=env)
+diff --git a/Lib/venv/__init__.py b/Lib/venv/__init__.py
+index 38e1bfe..b4f1cbd 100644
+--- a/Lib/venv/__init__.py
++++ b/Lib/venv/__init__.py
+@@ -310,6 +310,20 @@ def setup_python(self, context):
+             copier(context.executable, path)
+             if not os.path.islink(path):
+                 os.chmod(path, 0o755)
++                if (sysconfig.get_config_var('RELOCATABLE') == 'yes'
++                        and sysconfig.get_config_var('Py_ENABLE_SHARED')
++                        and not sysconfig.get_config_var('PYTHONFRAMEWORK')):
++                    # The copied executable searches relative to this environment.
++                    # Link the base library directory so it can find libpython.
++                    if sysconfig.is_python_build():
++                        library_dir = context.python_dir
++                    else:
++                        library_dir = os.path.join(sys.base_exec_prefix, 'lib')
++                    library_link = os.path.join(
++                        context.env_dir, 'lib', 'python-base')
++                    if os.path.islink(library_link):
++                        os.unlink(library_link)
++                    os.symlink(library_dir, library_link, target_is_directory=True)
+             for suffix in ('python', 'python3',
+                            f'python3.{sys.version_info[1]}'):
+                 path = os.path.join(binpath, suffix)
+diff --git a/Makefile.pre.in b/Makefile.pre.in
+index 7dcfc45..a090b9c 100644
+--- a/Makefile.pre.in
++++ b/Makefile.pre.in
+@@ -61,6 +61,10 @@ DSYMUTIL_PATH=  @DSYMUTIL_PATH@
+ 
+ GNULD=		@GNULD@
+ RELOCATABLE=	@RELOCATABLE@
++RELOCATABLE_PYTHON_LDFLAGS=@RELOCATABLE_PYTHON_LDFLAGS@
++RELOCATABLE_LIBPYTHON_LDFLAGS=@RELOCATABLE_LIBPYTHON_LDFLAGS@
++RELOCATABLE_EXTENSION_LDFLAGS=@RELOCATABLE_EXTENSION_LDFLAGS@
++RELOCATABLE_LIBPYTHON_INSTALL_NAME=@RELOCATABLE_LIBPYTHON_INSTALL_NAME@
+ 
+ # Shell used by make (some versions default to the login shell, which is bad)
+ SHELL=		/bin/sh -e
+@@ -313,6 +317,22 @@ LIBOBJS=	@LIBOBJS@
+ PYTHON=		python$(EXE)
+ BUILDPYTHON=	python$(BUILDEXE)
+ 
++# Build-tree programs run with RUNSHARED where needed. Install variants need
++# runtime paths relative to their installed locations.
++RELOCATABLE_DIR=build/relocatable
++INSTALL_PYTHON=$(BUILDPYTHON)
++INSTALL_LDLIBRARY=$(LDLIBRARY)
++INSTALL_PY3LIBRARY=$(PY3LIBRARY)
++INSTALL_SHAREDMODS=$(SHAREDMODS)
++ifeq ($(RELOCATABLE),yes)
++INSTALL_PYTHON=$(RELOCATABLE_DIR)/$(BUILDPYTHON)
++INSTALL_SHAREDMODS=$(addprefix $(RELOCATABLE_DIR)/,$(SHAREDMODS))
++ifeq ($(PY_ENABLE_SHARED),1)
++INSTALL_LDLIBRARY=$(RELOCATABLE_DIR)/$(LDLIBRARY)
++INSTALL_PY3LIBRARY=$(addprefix $(RELOCATABLE_DIR)/,$(PY3LIBRARY))
++endif
++endif
++
+ HOSTRUNNER= @HOSTRUNNER@
+ 
+ PYTHON_FOR_REGEN?=@PYTHON_FOR_REGEN@
+@@ -809,2 +829,3 @@ list-targets:
+ .PHONY: build_all
++build_all: $(INSTALL_PYTHON) $(INSTALL_LDLIBRARY) $(INSTALL_PY3LIBRARY) $(INSTALL_SHAREDMODS)
+ build_all:	check-clean-src check-app-store-compliance $(BUILDPYTHON) platform sharedmods \
+@@ -866,6 +887,10 @@ profile-opt: profile-run-stamp
+ 
+ # List of binaries that BOLT runs on.
+ BOLT_BINARIES := @BOLT_BINARIES@
++ifeq ($(RELOCATABLE),yes)
++# Optimize libraries before the interpreter, which depends on their timestamps.
++RELOCATABLE_BOLT_BINARIES = $(addprefix $(RELOCATABLE_DIR)/,$(filter-out $(BUILDPYTHON),$(BOLT_BINARIES)) $(BUILDPYTHON))
++endif
+ 
+ BOLT_INSTRUMENT_FLAGS := @BOLT_INSTRUMENT_FLAGS@
+ BOLT_APPLY_FLAGS := @BOLT_APPLY_FLAGS@
+@@ -875,13 +900,13 @@ clean-bolt:
+ 	# Profile data.
+ 	rm -f *.fdata
+ 	# Pristine binaries before BOLT optimization.
+-	rm -f *.prebolt
++	rm -f *.prebolt $(RELOCATABLE_DIR)/*.prebolt
+ 	# BOLT instrumented binaries.
+ 	rm -f *.bolt_inst
+ 
+ profile-bolt-stamp: $(BUILDPYTHON)
+ 	# Ensure a pristine, pre-BOLT copy of the binary and no profile data from last run.
+-	for bin in $(BOLT_BINARIES); do \
++	for bin in $(BOLT_BINARIES) $(RELOCATABLE_BOLT_BINARIES); do \
+ 	  prebolt="$${bin}.prebolt"; \
+ 	  if [ -e "$${prebolt}" ]; then \
+ 	    echo "Restoring pre-BOLT binary $${prebolt}"; \
+@@ -907,6 +932,14 @@ profile-bolt-stamp: $(BUILDPYTHON)
+ 	  @LLVM_BOLT@ "$${bin}.prebolt" -o "$${bin}.bolt" -data="$${bin}.fdata" $(BOLT_APPLY_FLAGS); \
+ 	  mv "$${bin}.bolt" "$${bin}"; \
+ 	done
++	# Install variants are linked from the same objects, so reuse the function profiles.
++	for bin in $(RELOCATABLE_BOLT_BINARIES); do \
++	  @LLVM_BOLT@ "$${bin}.prebolt" -o "$${bin}.bolt" -data="$${bin##*/}.fdata" $(BOLT_APPLY_FLAGS); \
++	  mv "$${bin}.bolt" "$${bin}"; \
++	done
++	if test "$(RELOCATABLE)" = yes && test -n "$(filter $(INSTSONAME),$(BOLT_BINARIES))"; then \
++	  $(LN) -f $(RELOCATABLE_DIR)/$(INSTSONAME) $(INSTALL_LDLIBRARY); \
++	fi
+ 	touch $@
+ 
+ .PHONY: bolt-opt
+@@ -974,6 +1007,10 @@ clinic-tests: check-clean-src $(srcdir)/Lib/test/clinic.test.c
+ $(BUILDPYTHON):	Programs/python.o $(LINK_PYTHON_DEPS)
+ 	$(LINKCC) $(PY_CORE_EXE_LDFLAGS) $(LINKFORSHARED) -o $@ Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS)
+ 
++$(RELOCATABLE_DIR)/$(BUILDPYTHON): Programs/python.o $(LINK_PYTHON_DEPS) $(INSTALL_LDLIBRARY)
++	@mkdir -p $(@D)
++	$(LINKCC) $(PY_CORE_EXE_LDFLAGS) $(LINKFORSHARED) $(RELOCATABLE_PYTHON_LDFLAGS) -L$(RELOCATABLE_DIR) -o $@ Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS)
++
+ platform: $(PYTHON_FOR_BUILD_DEPS) pybuilddir.txt
+ 	$(RUNSHARED) $(PYTHON_FOR_BUILD) -c 'import sys ; from sysconfig import get_platform ; print("%s-%d.%d" % (get_platform(), *sys.version_info[:2]))' >platform
+ 
+@@ -1019,6 +1056,18 @@ libpython$(LDVERSION).dylib: $(LIBRARY_OBJS)
+ 	 $(CC) -dynamiclib $(PY_CORE_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(prefix)/lib/libpython$(LDVERSION).dylib -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(SHLIBS) $(LIBC) $(LIBM); \
+ 
+ 
++$(RELOCATABLE_DIR)/libpython$(LDVERSION).so: $(LIBRARY_OBJS) $(DTRACE_OBJS)
++	@mkdir -p $(@D)
++	$(BLDSHARED) $(RELOCATABLE_LIBPYTHON_LDFLAGS) -Wl,-h$(INSTSONAME) -o $(RELOCATABLE_DIR)/$(INSTSONAME) $(LIBRARY_OBJS) $(MODLIBS) $(SHLIBS) $(LIBC) $(LIBM)
++	$(LN) -f $(RELOCATABLE_DIR)/$(INSTSONAME) $@
++
++$(RELOCATABLE_DIR)/libpython3.so: $(RELOCATABLE_DIR)/libpython$(LDVERSION).so
++	$(BLDSHARED) $(RELOCATABLE_LIBPYTHON_LDFLAGS) $(NO_AS_NEEDED) -o $@ -Wl,-hlibpython3.so $^
++
++$(RELOCATABLE_DIR)/libpython$(LDVERSION).dylib: $(LIBRARY_OBJS)
++	@mkdir -p $(@D)
++	$(CC) -dynamiclib $(PY_CORE_LDFLAGS) $(RELOCATABLE_LIBPYTHON_LDFLAGS) -undefined dynamic_lookup -Wl,-install_name,$(RELOCATABLE_LIBPYTHON_INSTALL_NAME) -Wl,-compatibility_version,$(VERSION) -Wl,-current_version,$(VERSION) -o $@ $(LIBRARY_OBJS) $(DTRACE_OBJS) $(SHLIBS) $(LIBC) $(LIBM)
++
+ libpython$(VERSION).sl: $(LIBRARY_OBJS)
+ 	$(LDSHARED) -o $@ $(LIBRARY_OBJS) $(MODLIBS) $(SHLIBS) $(LIBC) $(LIBM)
+ 
+@@ -2394,7 +2443,7 @@ sharedinstall: all
+ 			else    true; \
+ 			fi; \
+ 		done
+-		@for i in X $(SHAREDMODS); do \
++		@for i in X $(INSTALL_SHAREDMODS); do \
+ 		  if test $$i != X; then \
+ 		    echo $(INSTALL_SHARED) $$i $(DESTSHARED)/`basename $$i`; \
+ 		    $(INSTALL_SHARED) $$i $(DESTDIR)$(DESTSHARED)/`basename $$i`; \
+@@ -2408,7 +2457,7 @@ sharedinstall: all
+ # Install the interpreter with $(VERSION) affixed
+ # This goes into $(exec_prefix)
+ .PHONY: altbininstall
+-altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
++altbininstall: all @FRAMEWORKPYTHONW@
+ 	@for i in $(BINDIR) $(LIBDIR); \
+ 	do \
+ 		if test ! -d $(DESTDIR)$$i; then \
+@@ -2418,7 +2467,7 @@ altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
+ 		fi; \
+ 	done
+ 	if test "$(PYTHONFRAMEWORKDIR)" = "no-framework" ; then \
+-		$(INSTALL_PROGRAM) $(BUILDPYTHON) $(DESTDIR)$(BINDIR)/python$(LDVERSION)$(EXE); \
++		$(INSTALL_PROGRAM) $(INSTALL_PYTHON) $(DESTDIR)$(BINDIR)/python$(LDVERSION)$(EXE); \
+ 	else \
+ 		$(INSTALL_PROGRAM) $(STRIPFLAG) Mac/pythonw $(DESTDIR)$(BINDIR)/python$(LDVERSION)$(EXE); \
+ 	fi
+@@ -2433,13 +2482,13 @@ altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
+ 			if test -n "$(DLLLIBRARY)" ; then \
+ 				$(INSTALL_SHARED) $(DLLLIBRARY) $(DESTDIR)$(BINDIR); \
+ 			else \
+-				$(INSTALL_SHARED) $(LDLIBRARY) $(DESTDIR)$(LIBDIR)/$(INSTSONAME); \
++				$(INSTALL_SHARED) $(INSTALL_LDLIBRARY) $(DESTDIR)$(LIBDIR)/$(INSTSONAME); \
+ 				if test $(LDLIBRARY) != $(INSTSONAME); then \
+ 					(cd $(DESTDIR)$(LIBDIR); $(LN) -sf $(INSTSONAME) $(LDLIBRARY)) \
+ 				fi \
+ 			fi; \
+ 			if test -n "$(PY3LIBRARY)"; then \
+-				$(INSTALL_SHARED) $(PY3LIBRARY) $(DESTDIR)$(LIBDIR)/$(PY3LIBRARY); \
++				$(INSTALL_SHARED) $(INSTALL_PY3LIBRARY) $(DESTDIR)$(LIBDIR)/$(PY3LIBRARY); \
+ 			fi; \
+ 		else	true; \
+ 		fi; \
+diff --git a/Modules/makesetup b/Modules/makesetup
+index 8b28946..88c01c6 100755
+--- a/Modules/makesetup
++++ b/Modules/makesetup
+@@ -279,6 +279,9 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
+ 			rule="$file: $objs \$(MODULE_${mods_upper}_LDEPS)"
+ 			rule="$rule; \$(BLDSHARED) $objs $libs \$(MODULE_LDFLAGS_SHARED) -o $file"
+ 			echo "$rule" >>$rulesf
++			rule="\$(RELOCATABLE_DIR)/$file: $objs \$(MODULE_${mods_upper}_LDEPS)"
++			rule="$rule; @mkdir -p \$(@D); \$(BLDSHARED) $objs $libs \$(MODULE_LDFLAGS_SHARED) \$(RELOCATABLE_EXTENSION_LDFLAGS) -o \$@"
++			echo "$rule" >>$rulesf
+ 		done
+ 	done
+ 
+diff --git a/configure.ac b/configure.ac
+index 1afbeba..47741e6 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -6874,6 +6874,54 @@ AC_SUBST([BINLIBDEST])
+ LIBDEST='${prefix}/${PLATLIBDIR}/python$(VERSION)$(ABI_THREAD)'
+ BINLIBDEST='${exec_prefix}/${PLATLIBDIR}/python$(VERSION)$(ABI_THREAD)'
+ 
++# Runtime paths are specific to the installed location of each kind of binary.
++# Do not add them to LDSHARED: third-party extensions may be installed elsewhere.
++RELOCATABLE_PYTHON_LDFLAGS=
++RELOCATABLE_LIBPYTHON_LDFLAGS=
++RELOCATABLE_EXTENSION_LDFLAGS=
++RELOCATABLE_LIBPYTHON_INSTALL_NAME=
++AS_IF([test "$enable_relocatable" = yes && test -n "$enable_framework"], [
++  AC_MSG_ERROR([--enable-relocatable does not support framework builds yet])
++])
++AS_IF([test "$enable_relocatable" = yes && test -z "$enable_framework"], [
++  AS_CASE([$ac_sys_system],
++    [Linux|Darwin], [],
++    [AC_MSG_ERROR([relocatable builds are not implemented on $ac_sys_system yet])])
++  AS_VAR_IF([prefix], [NONE], [relocatable_prefix=$ac_default_prefix],
++    [relocatable_prefix=$prefix])
++  AS_IF([test "$exec_prefix" != NONE && test "$exec_prefix" != '${prefix}' && test "$exec_prefix" != "$relocatable_prefix"],
++    [AC_MSG_ERROR([--enable-relocatable requires a common prefix and exec-prefix])])
++  AS_IF([test "$bindir" != '${exec_prefix}/bin' && test "$bindir" != '${prefix}/bin' && test "$bindir" != "$relocatable_prefix/bin"],
++    [AC_MSG_ERROR([--enable-relocatable requires the default bin directory])])
++  AS_IF([test "$libdir" != '${exec_prefix}/lib' && test "$libdir" != '${prefix}/lib' && test "$libdir" != "$relocatable_prefix/lib"],
++    [AC_MSG_ERROR([--enable-relocatable requires the default lib directory])])
++  AS_CASE([$PLATLIBDIR], [*/*|.|..],
++    [AC_MSG_ERROR([--enable-relocatable requires a single directory name for --with-platlibdir])])
++  AS_CASE([$ac_sys_system],
++    [Linux], [
++      # Keep the dollar sign through configure, make, and the shell.
++      # DT_RPATH entries can also resolve indirect dependencies.
++      RELOCATABLE_PYTHON_LDFLAGS="-Wl,--disable-new-dtags,-rpath,'\$\$ORIGIN/../lib:\$\$ORIGIN/../lib/python-base'"
++      RELOCATABLE_LIBPYTHON_LDFLAGS="-Wl,--disable-new-dtags,-rpath,'\$\$ORIGIN'"
++      RELOCATABLE_EXTENSION_LDFLAGS="-Wl,--disable-new-dtags,-rpath,'\$\$ORIGIN/../../../lib'"
++      save_LDFLAGS=$LDFLAGS
++      LDFLAGS="$LDFLAGS -Wl,--disable-new-dtags"
++      AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])], [],
++        [AC_MSG_ERROR([--enable-relocatable requires linker support for --disable-new-dtags])])
++      LDFLAGS=$save_LDFLAGS
++    ],
++    [Darwin], [
++      RELOCATABLE_LIBPYTHON_INSTALL_NAME='@rpath/libpython$(LDVERSION).dylib'
++      RELOCATABLE_PYTHON_LDFLAGS='-Wl,-rpath,@executable_path/../lib -Wl,-rpath,@executable_path/../lib/python-base'
++      RELOCATABLE_LIBPYTHON_LDFLAGS='-Wl,-rpath,@loader_path'
++      RELOCATABLE_EXTENSION_LDFLAGS='-Wl,-rpath,@loader_path/../../../lib'
++    ])
++])
++AC_SUBST([RELOCATABLE_PYTHON_LDFLAGS])
++AC_SUBST([RELOCATABLE_LIBPYTHON_LDFLAGS])
++AC_SUBST([RELOCATABLE_EXTENSION_LDFLAGS])
++AC_SUBST([RELOCATABLE_LIBPYTHON_INSTALL_NAME])
++
+ dnl define LIBPL after ABIFLAGS and LDVERSION is defined.
+ AC_SUBST([PY_ENABLE_SHARED])
+ if test x$PLATFORM_TRIPLET = x; then
+diff --git a/Lib/test/test_venv.py b/Lib/test/test_venv.py
+index 2f30d31..5af4856 100644
+--- a/Lib/test/test_venv.py
++++ b/Lib/test/test_venv.py
+@@ -809,6 +809,8 @@ def test_zippath_from_non_installed_posix(self):
+         # LD_LIBRARY_PATH so the non-installed python can find and link
+         # libpython.so
+         ld_library_path = sysconfig.get_config_var("LIBDIR")
++        if sysconfig.get_config_var("RELOCATABLE") == "yes":
++            ld_library_path = os.path.join(sys.base_exec_prefix, "lib")
+         if not ld_library_path or sysconfig.is_python_build():
+             ld_library_path = os.path.abspath(os.path.dirname(sys.executable))
+         if sys.platform == 'darwin':
+@@ -827,7 +829,11 @@ def test_zippath_from_non_installed_posix(self):
+         # correct zip path in pythonpath.
+         target_python = os.path.join(self.env_dir, self.bindir, python_exe)
+         cmd = [target_python, '-S', '-c', 'import sys; print(sys.path)']
+-        out, err = check_output(cmd)
++        # This interpreter also depends on libraries outside the incomplete
++        # installation used by this test.
++        with EnvironmentVarGuard() as env:
++            env[ld_library_path_env] = ld_library_path
++            out, err = check_output(cmd)
+         self.assertTrue(zip_landmark.encode() in out)
+
+     @requireVenvCreate
diff --git a/pythonbuild/disttests/__init__.py b/pythonbuild/disttests/__init__.py
index d6ad302b8..b076efaac 100644
--- a/pythonbuild/disttests/__init__.py
+++ b/pythonbuild/disttests/__init__.py
@@ -45,6 +45,69 @@
 
 
 class TestPythonInterpreter(unittest.TestCase):
+    @unittest.skipUnless(
+        sys.platform in {"linux", "darwin"} and sys.version_info >= (3, 15),
+        "Relocatable build mode is enabled on Unix in Python 3.15+",
+    )
+    def test_relocatable_build_mode(self):
+        import sysconfig
+
+        self.assertEqual(sysconfig.get_config_var("RELOCATABLE"), "yes")
+        self.assertEqual(sysconfig.get_config_var("Py_ENABLE_RELOCATABLE"), 1)
+
+    @unittest.skipUnless(
+        sys.platform in {"linux", "darwin"}, "Unix shared-library search paths"
+    )
+    @unittest.skipIf(
+        "static" in os.environ["BUILD_OPTIONS"],
+        "Static builds have no shared libraries",
+    )
+    def test_extension_libraries_without_executable_rpath(self):
+        # PBS links libpython statically into the interpreter. A copy outside the
+        # installation cannot supply the extension's library path through its rpath.
+        with tempfile.TemporaryDirectory(prefix="disttests-relocatable-") as temp_dir:
+            root = Path(temp_dir)
+            executable = root / "bin" / Path(sys.executable).name
+            executable.parent.mkdir()
+            shutil.copy2(sys.executable, executable)
+            env = {
+                key: value
+                for key, value in os.environ.items()
+                if not key.startswith(("PYTHON", "LD_", "DYLD_"))
+            }
+            env["PYTHONHOME"] = sys.base_prefix
+
+            if "-linux-gnu" in os.environ["TARGET_TRIPLE"]:
+                # An incompatible ambient library must not override a bundled one.
+                poison = root / "poison"
+                poison.mkdir()
+                for pattern in ("libpython*.so*", "libtcl*.so*", "libtk*.so*"):
+                    for library in (Path(sys.base_prefix) / "lib").glob(pattern):
+                        (poison / library.name).write_bytes(b"not an ELF library")
+                env["LD_LIBRARY_PATH"] = str(poison)
+
+            probe = """
+import ctypes
+import pathlib
+import sys
+import _tkinter
+
+assert _tkinter.__file__
+abi3 = pathlib.Path(sys.base_prefix) / "lib" / "libpython3.so"
+if abi3.exists():
+    ctypes.CDLL(str(abi3))
+"""
+            result = subprocess.run(
+                [str(executable), "-S", "-c", probe],
+                cwd=root,
+                env=env,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.STDOUT,
+                text=True,
+                timeout=30,
+            )
+            self.assertEqual(result.returncode, 0, result.stdout)
+
     @unittest.skipUnless(os.name == "nt", "Windows executable names")
     def test_windows_executables(self):
         build_options = os.environ["BUILD_OPTIONS"].split("+")