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/gssapi_mech.h

@@ -519,6 +519,9 @@ typedef OM_uint32 GSSAPI_CALLCONV _gss_authorize_localname_t (
 	       gss_const_OID		/* user_name_type */
 	      );
 
+struct _gss_name;
+struct _gss_cred;
+
 /* mechglue internal */
 struct gss_mech_compat_desc_struct;
 
@@ -623,4 +626,41 @@ struct _gss_oid_name_table {
 extern struct _gss_oid_name_table _gss_ont_mech[];
 extern struct _gss_oid_name_table _gss_ont_ma[];
 
+int
+_gss_mg_log_level(int level);
+
+void
+_gss_mg_log(int level, const char *fmt, ...)
+    HEIMDAL_PRINTF_ATTRIBUTE((printf, 2, 3));
+
+void
+_gss_mg_log_name(int level,
+		 struct _gss_name *name,
+		 gss_OID mech_type,
+		 const char *fmt, ...);
+
+void
+_gss_mg_log_cred(int level,
+		 struct _gss_cred *cred,
+		 const char *fmt, ...);
+
+
+void
+_gss_load_plugins(void);
+
+gss_iov_buffer_desc *
+_gss_mg_find_buffer(gss_iov_buffer_desc *iov,
+		    int iov_count,
+		    OM_uint32 type);
+
+OM_uint32
+_gss_mg_allocate_buffer(OM_uint32 *minor_status,
+			gss_iov_buffer_desc *buffer,
+			size_t size);
+
+OM_uint32
+gss_mg_set_error_string(gss_OID mech,
+                       OM_uint32 maj, OM_uint32 min,
+                       const char *fmt, ...);
+
 #endif /* GSSAPI_MECH_H */