--- configure.ac.orig	2014-10-28 17:12:59 UTC
+++ configure.ac
@@ -732,7 +732,11 @@ dnl libgdbm for dbm_pagfno, so check for
 fi
 dnl check if dbm_open is part of libc
 if test "$ac_cv_lib_new_dbm" = "" -a "$ac_cv_header_ndbm_h" = "yes"; then
-  AC_CHECK_LIB(c, dbm_open, ac_cv_header_new_dbm="ndbm.h"; ac_cv_lib_new_dbm="c")
+  AC_CHECK_LIB(c, dbm_open, 
+dnl on FreeBSD dbm_open is in base libc, but if gdbm is installed with COMPAT
+dnl then GNU ndbm.h is present, so check if this is the case first.
+    AC_CHECK_LIB(gdbm_compat, dbm_pagfno, ac_cv_header_new_dbm="ndbm.h"; ac_cv_lib_new_dbm="gdbm -lgdbm_compat",
+      AC_CHECK_LIB(c, dbm_pagfno, ac_cv_header_new_dbm="ndbm.h"; ac_cv_lib_new_dbm="c")))
 fi
 if test "$ac_cv_lib_new_dbm" = "" -a "$ac_cv_header_db1_ndbm_h" = "yes"; then
   AC_CHECK_LIB(db1, dbm_open, ac_cv_header_new_dbm="db1/ndbm.h"; ac_cv_lib_new_dbm="db1")