configure: Allow compiling for x32.

Also do not require yasm for non-x86 architectures.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@37321 b3059339-0415-0410-9bf9-f77b7e298cf2
Fix GUI compilation errors after removal of the internal libdvd*.

The GUI did not compile without DVD support which is default
after r37317 now if there are no external DVD libraries available.

Reported by Giorgio Vazzana, mywing81 gmail com.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@37322 b3059339-0415-0410-9bf9-f77b7e298cf2