svn commit: r249665 - head

[Warner Losh]

Author: imp
Date: Sat Apr 20 01:12:23 2013
New Revision: 249665
URL: http://svnweb.freebsd.org/changeset/base/249665

Log:
  Add note about fagility of the clang upgrade process.

Modified:
  head/UPDATING

Modified: head/UPDATING
==============================================================================
--- head/UPDATING	Sat Apr 20 00:33:37 2013	(r249664)
+++ head/UPDATING	Sat Apr 20 01:12:23 2013	(r249665)
@@ -11,6 +11,11 @@ handbook:
 Items affecting the ports and packages system can be found in
 /usr/ports/UPDATING.  Please read that file before running portupgrade.
 
+NOTE: FreeBSD has switched from gcc to clang. If you have trouble bootstrapping
+from older versions of FreeBSD, try WITHOUT_CLANG and WITHOUT_CLANG_IS_CC to
+bootstrap to tip of head, and then rebuild without those options. The bootstrap
+process from older version of current is a bit fragile.
+
 NOTE TO PEOPLE WHO THINK THAT FreeBSD 10.x IS SLOW:
 	FreeBSD 10.x has many debugging features turned on, in both the kernel
 	and userland.  These features attempt to detect incorrect use of