Apply ldflags-order part of ldflags_order patch from Alberto Villa.

Apply ldflags-order part of ldflags_order patch from Alberto Villa.

Alberto wrote:
"on freebsd (as well as on linuces without /usr/local/lib in default ld path)
building concurrent versions of mlt is not possible, because of the wrong
linking of -lmlt while using LDFLAGS=-L/usr/local/lib
this patch fixes the issue using pkg-config"

Signed-off-by: Dan Dennedy <dan@dennedy.org>

git-svn-id: https://mlt.svn.sourceforge.net/svnroot/mlt/trunk/mlt@1416 d19143bc-622f-0410-bfdd-b5b2a6649095