The macro hell sometimes make it difficult to trace the source of
an error, so it is easier to analyze the preprocessed output.
This patch makes this automatical by specifying DBG=1 on the
command line: a file ffmpeg/dir/file.asm gets preprocessed to
builddir/dir/file.dbg.asm, which is then compiled.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Split normal build system documentation and the fate one.
Document THREADS make variable and provide an introduction to fate.
Document DESTDIR make variable and add some generic targets.