Linux pkg-config files are incorrect

[FreezyLemon]

Hi, I have some trouble with the .pc files in the linux releases.

The files start with

prefix=${pcfiledir}/../..
exec_prefix=${prefix}
libdir=${prefix}/lib
includedir=${prefix}/include

Now, as a reminder, the file structure for the linux builds is:

ffmpeg-7.1-linux-clang-lite
├── bin
│   ├── amd64
│   ├── arm64
│   └── armhf
├── include
│   ├── libavcodec
│   ├── libavdevice
│   ├── libavfilter
│   ├── libavformat
│   ├── libavutil
│   ├── libswresample
│   └── libswscale
└── lib
    ├── amd64
    │   └── pkgconfig
    ├── arm64
    │   └── pkgconfig
    └── armhf
        └── pkgconfig

This resolves to the following:

prefix="ffmpeg-7.1-linux-clang-lite/lib" (incorrect)
exec_prefix=${prefix}
libdir=${prefix}/lib (this is now `.../lib/lib`)
includedir=${prefix}/include (this is now `../lib/include`)

You can also see this when running pkg-config:

# Extract ffmpeg to /tmp/ffmpeg-dl/ffmpeg-7.1-linux-clang-lite
$ PKG_CONFIG_PATH=/tmp/ffmpeg-dl/ffmpeg-7.1-linux-clang-lite/lib/amd64/pkgconfig pkg-config --cflags libavcodec
> -I/tmp/ffmpeg-dl/ffmpeg-7.1-linux-clang-lite/lib/amd64/pkgconfig/../../include

$ realpath /tmp/ffmpeg-dl/ffmpeg-7.1-linux-clang-lite/lib/amd64/pkgconfig/../../include
> /tmp/ffmpeg-dl/ffmpeg-7.1-linux-clang-lite/lib/include

I believe this would be fixed by setting prefix=${pcfiledir}/../../.. (one directory higher) and setting libdir=${prefix}/lib/<arch>, arch being amd64, arm64 etc.

[wang-bin]

script is fixed in master branch. only ffmpeg master branch prebuilt packages are patched

[wang-bin]

I see your docker is using ffmpeg 4.4 5.1 6.1 7.0 and 7.1，now prebuilt packages for these versions are updated, no need to patch pc files. btw, my build depends on libc++ instead of libstdc++ because libc++ abi is more stable, you have to install libc++1 using apt.

[FreezyLemon]

Thank you! This is very useful for us. I'll make sure to install libc++, that's not a big deal.