libyuv: add pkg-config .pc file

pkgs/development/libraries/libyuv/default.nix

···
     ./link-library-against-libjpeg.patch
   ];
 
+  postPatch = ''
+    mkdir -p $out/lib/pkgconfig
+    cp ${./yuv.pc} $out/lib/pkgconfig/libyuv.pc
+
+    substituteInPlace $out/lib/pkgconfig/libyuv.pc \
+      --replace "@PREFIX@" "$out" \
+      --replace "@VERSION@" "$version"
+  '';
+
   meta = with lib; {
     homepage = "https://chromium.googlesource.com/libyuv/libyuv";
     description = "Open source project that includes YUV scaling and conversion functionality";

pkgs/development/libraries/libyuv/yuv.pc

···
+prefix=@PREFIX@
+exec_prefix=${prefix}
+libdir=${prefix}/lib
+includedir=${prefix}/include
+
+Name: yuv
+Description: WebM Project Yuv codec implementation
+Version: @VERSION@
+Requires:
+Conflicts:
+Libs: -L${libdir} -lyuv -lm
+Libs.private: -lm -lpthread
+Cflags: -I${includedir}