Fix includedir/libdir in pkg-config file when CMAKE_INSTALL_INCLUDEDIR/CMAKE_INSTALL_LIBDIR are absolute paths

[abustany]

This fixes the pkg-config file generation to properly join paths when computing libdir/includedir.

Relevant CMake documentation
More info in the Nix bugtracker

I ran into that issue while adding OpenJPH to nixpkgs. For now this commit is maintained as a patch in Nix.

[aous72]

Hi Adrian,

Thank you for putting this.
I am happy to merge it.
Do I need to worry about breaking other repos installation scripts? I am not super familiar what the current trend is.

Thank you.

Kind regards,
Aous.

[abustany]

As far as I understand, this change should not break anything. For the record, here's the diff between the old and the new pc file when running cmake -DCMAKE_INSTALL_PREFIX=/usr:

--- openjph.pc.old	2024-07-03 09:08:23.779830131 +0200
+++ openjph.pc	2024-07-03 09:08:40.028517484 +0200
@@ -3,7 +3,7 @@
 Version: 0.14.0
 Requires: 
 prefix=/usr
-includedir=${prefix}/include
-libdir=${prefix}/lib64
+includedir=/usr/include
+libdir=/usr/lib64
 Libs: -L${libdir} -lopenjph
 Cflags: -I${includedir}

in this simple case, there's no difference besides the fact that the prefix is now "baked" in includedir/libdir.

The old code breaks however if CMAKE_INSTALL_INCLUDEDIR or CMAKE_INSTALL_INCLUDEDIR are absolute paths, because ${prefix} gets prepended unconditionally. The _FULL variables, on the other hand, handle those cases correctly.

Nix is probably one of the few cases where those flags are set to absolute paths, Nix uses that to output the files in different prefixes that correspond to different subpackages (one for binaries, one for development headers).

[aous72]

Than you Adrien.

[kmilos]

Do I need to worry about breaking other repos installation scripts?

YES!

The _FULL variables, on the other hand, handle those cases correctly.

This doesn't work on systems that need relocatable packages and rely on relative paths, like Windows, multilib/virtual envs for doing cross-compiling etc.

The way to solve this properly and once and for all is e.g.

zeux/pugixml#611

Please release 0.14.2 as soon as possible w/ a proper fix. @aous72

[kmilos]

Furthermore, I suggest dropping PKG_CONFIG_LIBS and PKG_CONFIG_CFLAGS, just hard-code them straight in the .pc file until a real need arises.

[aous72]

Hi @kmilos,

Please let me know if Release 0.14.2 works for you.

Also, @abustany, please let me know if Release 0.14.2 works for you.

Kind regards,
Aous.

[kmilos]

Looks good to me, thank you on a rapid response!

[abustany]

@aous72 it works! And @kmilos sorry for breaking the windows build, I only tested on UNIX...