diff --git a/configure.ac b/configure.ac
index 8095dfcf1d..2bdb3dc3ed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1562,6 +1562,7 @@ fi
 if test "$with_gssapi" = yes ; then
   AC_CHECK_HEADERS(gssapi/gssapi.h, [],
 	[AC_CHECK_HEADERS(gssapi.h, [], [AC_MSG_ERROR([gssapi.h header file is required for GSSAPI])])])
+	[AC_CHECK_HEADERS(gssapi_ext.h, [], [AC_MSG_ERROR([gssapi_ext.h header file is required for GSSAPI])])])
 fi
 
 PGAC_PATH_PROGS(OPENSSL, openssl)