diff --git a/configure.ac b/configure.ac
index bbf854cc..320f0225 100644
--- a/configure.ac
+++ b/configure.ac
@@ -427,7 +427,8 @@ AC_ARG_WITH([libgssapi_krb5], [AS_HELP_STRING([--with-libgssapi_krb5],
 # conditionally require libgssapi_krb5
 if test "x$require_libgssapi_krb5_ext" != "xno"; then
     AC_CHECK_HEADERS(gssapi/gssapi_generic.h)
-    AC_SEARCH_LIBS([gss_init_sec_context], [gssapi_krb5 gssapi],,
+    AC_SEARCH_LIBS([gss_init_sec_context], [gssapi_krb5 gssapi],
+        AC_DEFINE(HAVE_LIBGSSAPI_KRB5, [1], [Enabled GSSAPI security]),
         AC_MSG_ERROR(libgssapi_krb5 is needed for GSSAPI security))
 fi