-- Make a pass at cleaning up contrib/ Makefile.am files
-- Rename many AM_CONDITIONALS for consistency and give them better names to
   better indicate what they mean
-- Remove some dead input plugin tests
-- Clean up AM_PATH_DVDNAV

-- Removed m4/optimizations.m4, and along with it, AC_OPTIMIZATIONS.
-- Stripped down, cleaned up, and merged the former together with other compiler
   characteristic checks.
-- Do not set any optimization flags into CFLAGS.  Update all Makefile.am's with
   proper AM_CFLAGS, AM_CPPFLAGS, AM_LDFLAGS, etc. to set up optimization flags,
   usually from DEFAULT_OCFLAGS.
-- Start cleaning up CFLAGS/CPPFLAGS stuff in Makefile.am's all over the place.
-- Correct a number of places where CFLAGS itself was being mangled in
   Makefile to on-the-fly adjust optimizations to work around compiler bugs.
   This stuff is now done correctly.
-- The run of automake from autogen.sh is now clean of warnings.
-- Cleaned out some (now) dead macros from m4/_xine.m4
-- Mac OS X intel builds out-of-the-box now -- dropped optimization on
   post/deinterlace/plugins/kdetv-greedyh to O1_CFLAGS.
-- OBJCFLAGS is now getting set correctly everywhere that it needs to be
-- Various other miscellaneous cleanups all over

libdca 0.0.5 was released about a week ago, and this commit replaces the old
code from libdts 0.0.2 (that was renamed libdca).

There's basically no functional change even if the build system is simplified
as configure takes care of switching between the two implementations on its
own.