diff --git a/init/init.lisp b/init/init.lisp
index 24d730ec9a31f4d254d02f02b6c2bb1f6824454f..228d5dc57d5f351bd7fa9ffe76739d8e637b791e 100644
--- a/init/init.lisp
+++ b/init/init.lisp
@@ -1,12 +1,18 @@
 ;; Load GSL
 ;; Liam Healy Sat Mar  4 2006 - 18:53
-;; Time-stamp: <2009-05-25 16:32:45EDT init.lisp>
+;; Time-stamp: <2009-08-22 16:19:52EDT init.lisp>
 ;; $Id$
 
 (defpackage gsll
   (:nicknames :gsl)
   (:use :common-lisp :cffi))
 
+;;; When installed through Mac Ports, GSL .h files will be found
+;;; in /opt/local/include.
+#+darwin
+(setf cffi-grovel::*cc-flags*
+      (append '("-I" "/opt/local/include/") cffi-grovel::*cc-flags*))
+
 (cffi:define-foreign-library libgslcblas
     (:darwin
      (:or "/opt/local/lib/libgslcblas.dylib" "/sw/lib/libgslcblas.dylib"