[fhgffy]

The pkg-config linker flags omit -L${libdir} for /usr, /usr/local, or the default prefix even when --libdir or --exec-prefix installs the library elsewhere. The install succeeds, but a pkg-config consumer cannot find -lmxml4.

The final change compares the effective library directory, retaining the existing omission of -L for /usr/lib and /usr/local/lib and adding it for other directories. Expansion is confined to a subshell used for that comparison; the public install variables and the .pc file keep their original expressions. configure is regenerated exactly with Autoconf 2.71.

The narrower behavior follows the review about multiple installed library versions. An actual MiniXML v3/v4 static-library control reproduces the overly broad earlier patch selecting the wrong libmxml.a and failing on a v3-only symbol; the narrowed patch preserves the base selection and links/runs successfully.

Current Linux/GCC 13.3 validation covers 14 configurations, each with configure/build/upstream test/staged install/consumer checks. Five custom-directory base consumers fail without the missing -L and pass with that single-path control; the final patch passes all custom cases and default multi-version controls. Symbolic libdir/exec-prefix cases retain their expressions. Exact Autoconf regeneration, shell syntax, encoding, and git diff --check pass. Windows/macOS and current hosted CI are separate and were not run locally.

[michaelrsweet]

I have concerns because I added these checks specifically because I ran into problems...

The "-L" option interacts poorly when you have multiple versions of the same library installed in different directories... :/

[fhgffy]

You are right about the version-selection risk. I reproduced the earlier patch selecting a default-directory MiniXML v4 archive over the intended v3 archive. In a4ad22c, I kept the original /usr/lib and /usr/local/lib suppression and compare the effective libdir, so only custom library directories get -L. Expansion stays in a subshell and does not freeze the install variables. All 14 configuration/build/test/install/consumer cases pass locally, including symbolic directories, and the real v3/v4 link control now selects the same library as the base.

[michaelrsweet]

Try the following changes:

[master 601f75b] Update pkg-config include/library directories (Issue #359)

[fhgffy]

Tested 601f75b. One case still reproduced the version-selection problem: --prefix=/usr --libdir='${prefix}/lib' retains -L/usr/lib because the directory comparison uses the unexpanded value. With real v3 and v4 archives in separate search directories, that selected v4 over the intended v3. Merged your changes in 821e5ba and kept a subshell expansion only for the system-directory comparison; the include/exec-prefix changes are retained, and custom directories still get -L.

On WSL Linux/GCC 13.3, all 14 configuration/build/upstream-test/install/consumer cases pass. The strict custom-directory consumers pass without LIBRARY_PATH, and removing their -L fails in all eight controls. The three real v3/v4 selection controls, including the symbolic system directory, now select the intended v3 archive. System-directory DESTDIR consumers use an explicit staging search path, and the v3 archive is the previously built fixture. Native Windows/macOS tests have not been run locally.

[michaelrsweet]

This should take care of the case where you using "prefix" instead of "exec_prefix":

[master bbc60d7] Also check for libdir set using prefix (Issue #359)