1) HAVE_X is not needed. lavplay builds and runs on both Linux and OSX
(10.4 and 10.5) fine without it.
2) HAVE_X causes a build failure on OSX 10.5:
ld: cycle in dylib re-exports with /usr/X11/lib/libGL.dylib
Removing HAVE_X from configure.ac and lavtools/Makefile.am resolves the error
