Fix X11 and freetype include and library paths.

https://github.com/uniconproject/unicon/issues/562
--- configure.ac.orig	2026-04-02 03:40:09.000000000 -0500
+++ configure.ac	2026-04-02 03:43:22.000000000 -0500
@@ -565,7 +565,7 @@
      *bsd*)
         ;;
      *macos*)
-        XLIBS="-L/opt/X11/lib -L/usr/X11R6/lib -L/usr/local/lib -lXpm -lX11"
+        XLIBS="-L@PREFIX@/lib -lXpm -lX11"
 	;;
      *windows*)
         ;;
--- src/iconc/ccomp.c.orig	2020-12-20 23:08:43.000000000 -0600
+++ src/iconc/ccomp.c	2026-03-31 01:12:58.000000000 -0500
@@ -263,7 +263,7 @@
 #ifdef Graphics
 #ifdef MacOS
    buf = growcat(buf, &buflen, 1,
-	 " -I/usr/X11/include  -I/usr/X11 -I/usr/X11/include/freetype2 -L/usr/X11/lib");
+	 " -I@PREFIX@/include -I@PREFIX@/include/freetype2 -L@PREFIX@/lib");
 #endif
 #endif					/* Graphics */
 
--- src/common/Makefile.orig	2020-12-20 23:08:43.000000000 -0600
+++ src/common/Makefile	2026-03-31 01:12:17.000000000 -0500
@@ -89,7 +89,7 @@
 drawstring3d.$(O): drawstring3d.cc
 	@if test "`which $(CXX)`" != "" ; then \
 		echo "Got C++, building drawstring3d.o"; \
-		$(CXX) -c $(CPPFLAGS) $(CXXFLAGS) -I/usr/include/freetype2 -I/opt/X11/include/freetype2 -o drawstring3d.o drawstring3d.cc; \
+		$(CXX) -c $(CPPFLAGS) $(CXXFLAGS) -I@PREFIX@/include/freetype2 -o drawstring3d.o drawstring3d.cc; \
 	else \
 		echo "No C++, too bad"; \
 		echo "extern void syserr(char*); int cpp_drawstring3d(double x, double y, double z, char *s, char *f, int t, int size, void **tfont) { syserr(\"no C++; it is required for 3d fonts\"); return -1; } " > drawstring3d.c ; \