contrib: FreeType: require GPL

Otherwise, there is an advertising clause (which there are currently no
ways to handle in contrib).

contrib/src/freetype2/rules.mak

@@ -3,7 +3,9 @@
 FREETYPE2_VERSION := 2.7.1
 FREETYPE2_URL := $(SF)/freetype/freetype2/$(FREETYPE2_VERSION)/freetype-$(FREETYPE2_VERSION).tar.gz
 
+ifdef GPL
 PKGS += freetype2
+endif
 ifeq ($(call need_pkg,"freetype2"),)
 PKGS_FOUND += freetype2
 endif
@@ -21,6 +23,7 @@ freetype: freetype-$(FREETYPE2_VERSION).tar.gz .sum-freetype2
 DEPS_freetype2 = zlib $(DEPS_zlib)
 
 .freetype2: freetype
+	$(REQUIRE_GPL)
 	cd $< && cp builds/unix/install-sh .
 	sed -i.orig s/-ansi// $</builds/unix/configure
 	cd $< && GNUMAKE=$(MAKE) $(HOSTVARS) ./configure --with-harfbuzz=no --with-zlib=yes --without-png --with-bzip2=no $(HOSTCONF)