Further cleanup of autoconf output files for GSSAPI changes.

Running autoheader was missed in f7431bc.  This is cosmetic since
we aren't using these HAVE_ symbols, but let's get everything in
sync while we're looking at this.

Discussion: https://postgr.es/m/2422362.1681741814@sss.pgh.pa.us

Author: tglsfdc

src/include/pg_config.h.in

@@ -196,6 +196,12 @@
 /* Define to 1 if you have the `getpeerucred' function. */
 #undef HAVE_GETPEERUCRED
 
+/* Define to 1 if you have the <gssapi_ext.h> header file. */
+#undef HAVE_GSSAPI_EXT_H
+
+/* Define to 1 if you have the <gssapi/gssapi_ext.h> header file. */
+#undef HAVE_GSSAPI_GSSAPI_EXT_H
+
 /* Define to 1 if you have the <gssapi/gssapi.h> header file. */
 #undef HAVE_GSSAPI_GSSAPI_H