diff --git a/graphics/Mesa3/Makefile b/graphics/Mesa3/Makefile
index 6a3ab8afd701..6b17ab4fe2e6 100644
--- a/graphics/Mesa3/Makefile
+++ b/graphics/Mesa3/Makefile
@@ -53,6 +53,9 @@ MAKE_ENV+=	SUB_GL=${SUB_GL}		\
 pre-patch:
 	@${PERL} -pi -e 's|-lpthread|-pthread|g' ${WRKSRC}/configure
 
+post-configure:
+	@${PERL} -pi -e 's|%%PREFIX%%|${PREFIX}|' ${WRKSRC}/src/config.c
+
 post-install:
 .for lib in GL GLU
 	@${LN} -sf ${PREFIX}/lib/lib${lib}.so ${PREFIX}/lib/libMesa${lib}.so
diff --git a/graphics/Mesa3/files/patch-ae b/graphics/Mesa3/files/patch-ae
new file mode 100644
index 000000000000..295ebbb601f6
--- /dev/null
+++ b/graphics/Mesa3/files/patch-ae
@@ -0,0 +1,11 @@
+--- src/config.c	2000/09/11 12:25:04	1.1
++++ src/config.c	2000/09/11 12:25:27
+@@ -406,7 +406,7 @@
+ #if defined(__WIN32__) || defined(__MSDOS__)
+    const char *filename = "mesa.cnf";
+ #else
+-   const char *filename = "/etc/mesa.conf"; 
++   const char *filename = "%%PREFIX%%/etc/mesa.conf"; 
+ #endif   
+    FILE *file;
+    struct cnode *list;
diff --git a/graphics/mesagl/Makefile b/graphics/mesagl/Makefile
index 6a3ab8afd701..6b17ab4fe2e6 100644
--- a/graphics/mesagl/Makefile
+++ b/graphics/mesagl/Makefile
@@ -53,6 +53,9 @@ MAKE_ENV+=	SUB_GL=${SUB_GL}		\
 pre-patch:
 	@${PERL} -pi -e 's|-lpthread|-pthread|g' ${WRKSRC}/configure
 
+post-configure:
+	@${PERL} -pi -e 's|%%PREFIX%%|${PREFIX}|' ${WRKSRC}/src/config.c
+
 post-install:
 .for lib in GL GLU
 	@${LN} -sf ${PREFIX}/lib/lib${lib}.so ${PREFIX}/lib/libMesa${lib}.so
diff --git a/graphics/mesagl/files/patch-ae b/graphics/mesagl/files/patch-ae
new file mode 100644
index 000000000000..295ebbb601f6
--- /dev/null
+++ b/graphics/mesagl/files/patch-ae
@@ -0,0 +1,11 @@
+--- src/config.c	2000/09/11 12:25:04	1.1
++++ src/config.c	2000/09/11 12:25:27
+@@ -406,7 +406,7 @@
+ #if defined(__WIN32__) || defined(__MSDOS__)
+    const char *filename = "mesa.cnf";
+ #else
+-   const char *filename = "/etc/mesa.conf"; 
++   const char *filename = "%%PREFIX%%/etc/mesa.conf"; 
+ #endif   
+    FILE *file;
+    struct cnode *list;