contrib: freetype: build with PIC

I got a Linux x86-64 build complaining it was not built with PIC.

/usr/bin/ld: /root/build/contrib/x86_64-linux-gnu/lib/libfreetype.a(truetype.c.o): warning: relocation against `TT_RunIns' in read-only section `.text'
/usr/bin/ld: /root/build/contrib/x86_64-linux-gnu/lib/libfreetype.a(truetype.c.o): relocation R_X86_64_PC32 against symbol `TT_RunIns' can not be used when making a shared object; recompile with -fPIC

contrib/src/freetype2/rules.mak

@@ -29,7 +29,7 @@ ifndef AD_CLAUSES
 	$(REQUIRE_GPL)
 endif
 	$(CMAKECLEAN)
-	$(HOSTVARS) $(CMAKE) $(FREETYPE_CONF)
+	$(HOSTVARS) $(CMAKE_PIC) $(FREETYPE_CONF)
 	+$(CMAKEBUILD)
 	$(CMAKEINSTALL)
 	touch $@