pkgconfig/fmt.pc is overwritten between debug and release builds

[gh-andre]

When I install debug and release fmt libraries via CMake, the last one overwrites plgconfig configuration.

For example, I download fmt-8.1.0.zip and extract it into fmt-8.1.0 in the current directory and build it as follows:

FMT_VER=8.1.0

cmake -S fmt-${FMT_VER}
      -B fmt-${FMT_VER}/Release
      -DFMT_TEST=OFF
      -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE
      -DCMAKE_BUILD_TYPE=Release

cmake -S fmt-${FMT_VER}
      -B fmt-${FMT_VER}/Debug
      -DFMT_TEST=OFF
      -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE
      -DCMAKE_BUILD_TYPE=Debug

cmake --build fmt-${FMT_VER}/Release
cmake --build fmt-${FMT_VER}/Debug

cmake --install fmt-${FMT_VER}/Release
cmake --install fmt-${FMT_VER}/Debug

This generates a single /usr/local/lib64/pkgconfig/fmt.pc file, so when I run pkg-config --libs fmt, it returns -L/usr/local/lib64 -lfmtd.

This is not a problem on build machines because there's typically no debug libraries built or installed, but on developer machines it leads to linking problems.

From another issue (#1264 (comment)) I see that fmt.pc is intended for release builds, but that would make it more complicated to use it in make files that build both types.

I reworked my make files to use just fmt libraries appropriate for each build type, so this is more of an FYI.

[vitaut]

You could probably control the install location via normal CMake methods and separate debug/release binaries and configs.

this is more of an FYI

Closing the issue then.