Add CC/CFLAGS OS type detection code to plugins/c_src.mk
Allow $DIALYZER_OPTS to add more source directories

The current ordering of args in the dialyzer command don't allow additional
source directories to be specified. Putting --no_native first allows the
beginning of the $DIALYZER_OPTS to specify additional directories of files
to be analyzed.
Merge branch 'jj1bdx-cc-cflags' of git://github.com/jj1bdx/erlang.mk
Merge branch 'patch-1' of git://github.com/jaynel/erlang.mk