Contribs: add mfx dispatcher (Media SDK) for Win32

contrib/src/mfx/rules.mak

+# mfx (Media SDK)
+
+mfx_GITURL := git://git.videolan.org/mfx_dispatch
+
+ifdef HAVE_WIN32
+ifeq ($(call need_pkg,"mfx"),)
+PKGS_FOUND += mfx
+endif
+endif
+
+$(TARBALLS)/mfx-git.tar.xz:
+	$(call download_git,$(mfx_GITURL))
+
+.sum-mfx: mfx-git.tar.xz
+	$(warning $@ not implemented)
+	touch $@
+
+mfx: mfx-git.tar.xz
+	$(UNPACK)
+	cd $(UNPACK_DIR) && autoreconf -ivf
+	$(MOVE)
+
+.mfx: mfx
+	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
+	cd $< && $(MAKE) install
+	touch $@