zynaddsubfx: fix PIE

srcpkgs/zynaddsubfx/template

@@ -31,8 +31,10 @@ post_build() {
 	local ext
 	for ext in Spliter Controller; do
 		cd ${wrksrc}/ExternalPrograms/${ext}
-		# Replace gcc with the target C compiler
-		sed -i Makefile -e "s;gcc;${CC};g"
+		sed -i Makefile \
+			-e 's;`fltk-config --cflags`;& ${CFLAGS};' \
+			-e 's;`fltk-config --ldflags`;& ${LDFLAGS};' \
+			-e 's;gcc ;${CC} ;'
 		# Build external program
 		make ${makejobs}
 	done