[Fontconfig] cross compile use fails

[Roger Pack]

As a note, after cross compiling a static fontconfig, I get a .pc file
like this:

$ cat ./builds/win32/fontconfig-2.10.1/fontconfig.pc
prefix=/home/rogerdpack/dev/ffmpeg-windows-build-helpers/builds/mingw-w64-i686/i686-w64-mingw32
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include
sysconfdir=${prefix}/etc
localstatedir=${prefix}/var
PACKAGE=fontconfig
confdir=${sysconfdir}/fonts
cachedir=WINDOWSTEMPDIR_FONTCONFIG_CACHE

Name: Fontconfig
Description: Font configuration and customization library
Version: 2.10.1
Libs: -L${libdir} -lfontconfig
Libs.private:  -L/home/rogerdpack/dev/ffmpeg-windows-build-helpers/builds/mingw-w64-i686/i686-w64-mingw32/lib
-lexpat   -L/home/rogerdpack/dev/ffmpeg-windows-build-helpers/builds/mingw-w64-i686/i686-w64-mingw32/lib
-lfreetype
Cflags: -I${includedir}


When it actually gets used, it fails because it is missing "-lexpat"
and "-lfreetype" in the Libs: section.  Or at least, adding those to
the .pc causes linking with it to work.

Thanks for fontconfig!
-roger-