to LDFLAGS so linker finds them when using --as-needed (which is default
in some installations). Using --as-needed is generally a good thing, so
add that explicitly as well.
Originally committed as revision 5362 to svn://svn.ffmpeg.org/ffmpeg/trunk
This is needed for components that override install locations (libpostproc).
Originally committed as revision 5036 to svn://svn.ffmpeg.org/ffmpeg/trunk
