--- src/external/pac_responder.m4	
+++ src/external/pac_responder.m4	
@@ -14,7 +14,7 @@ then
     PKG_CHECK_MODULES(NDR_KRB5PAC, ndr_krb5pac, ndr_krb5pac_ok=yes,
         AC_MSG_WARN([Cannot build pac responder without libndr_krb5pac]))
-    AC_PATH_PROG(KRB5_CONFIG, krb5-config)
+    AC_PATH_PROG(KRB5_CONFIG, krb5-config, [], [/usr/local/bin:$PATH])
     AC_MSG_CHECKING(for supported MIT krb5 version)
     KRB5_VERSION="`$KRB5_CONFIG --version`"
     case $KRB5_VERSION in
@@ -23,7 +23,11 @@ then
         Kerberos\ 5\ release\ 1.11* | \
         Kerberos\ 5\ release\ 1.12* | \
         Kerberos\ 5\ release\ 1.13* | \
-        Kerberos\ 5\ release\ 1.14*)
+        Kerberos\ 5\ release\ 1.14* | \
+        Kerberos\ 5\ release\ 1.15* | \
+        Kerberos\ 5\ release\ 1.16* | \
+        Kerberos\ 5\ release\ 1.17* | \
+        Kerberos\ 5\ release\ 1.18*)
             krb5_version_ok=yes
             AC_MSG_RESULT([yes])
             ;;