gss: merge enhanced Apple mechglue logging

Add _gss_mg_log() and friends for logging from within the mechanism glue and
SPNEGO. These APIs wrap around the libkrb5 logging APIs.

lib/gssapi/mech/gss_acquire_cred_from.c

@@ -219,6 +219,11 @@ gss_acquire_cred_from(OM_uint32 *minor_status,
 	    continue;
         }
 
+	_gss_mg_log_name(10, name, &mechs->elements[i],
+			 "gss_acquire_cred %s name: %ld/%ld",
+			 m->gm_name,
+			 (long)major_status, (long)*minor_status);
+
 	HEIM_TAILQ_INSERT_TAIL(&cred->gc_mc, mc, gmc_link);
 
 	if (cred_time < min_time)
@@ -253,6 +258,8 @@ gss_acquire_cred_from(OM_uint32 *minor_status,
     if (time_rec)
         *time_rec = min_time;
 
+    _gss_mg_log_cred(10, cred, "gss_acquire_cred_from");
+
 cleanup:
     if (major_status != GSS_S_COMPLETE) {
 	gss_release_cred(&minor, (gss_cred_id_t *)&cred);