MJPEG Tools Svn

Remove unused variables so warning errors don't appear at compile time.

Remove the PRID64_STRING_FORMAT and PRId64 stuff and simply use %lld. The
only 2 uses of PRID64 and PRId64 were two debug statements mpeg2enc/ratectl.cc,
putseq.cc). Interestingly enough all the other int64_t printing was already
done with %lld ;)

More build improvements:

o Concocted a "ACX_CONFIG_PREFIXED_HEADER" macro, to create an installable
config header (mjpegtools-config.h -- not used yet)
o Removed extraneous AC_SUBSTS (that are already created within macros).
o Re-instate "HAVE_LIBDV" ac_define, which was accidentally axed earlier.
o Changed "dv", "quicktime", "png" to be consistently "libdv", "libquicktime",
and "libpng".
o Account for those changes in 'lavtools/Makefile.am'.
o A little modernization of 'lavtools/Makefile.am'

Portability patch submitted by Jacob Meuser

Removed vestigial "-export-dynamic" from shared-library build options.

add a missing '-' in the long form of nonvideo-bitrate option

SVCD encoding/multiplexing has been working for a long time - check this item off the PLANS.

By popular demand 'a' was changed to 'A' for the sample aspect option

Add '-a sar' option with a default of 1:1

Added jpeg2yuv's missing dependency on the JPEG libraries (since it directly
uses jpeg_() functions from those libraries).