--- configure.ac.orig	2008-07-17 22:34:51.000000000 -0400
+++ configure.ac	2008-07-17 22:35:56.000000000 -0400
@@ -83,6 +83,9 @@
 
 AC_CHECK_LIB(X11,XOpenDisplay,,[AC_MSG_ERROR([X11 library missing])])
 
+## Need libf2c for MOPAC
+AC_CHECK_LIB(f2c,i_len)
+
 ## are the rest necessary???
 
 AC_CHECK_LIB(Xmu,XmuDrawLogo)