svn commit: r349837 - stable/11

[Warner Losh]

Author: imp
Date: Mon Jul  8 15:41:40 2019
New Revision: 349837
URL: https://svnweb.freebsd.org/changeset/base/349837

Log:
  Add note about upgrading from RELENG_10.
  
  When upgrading from RELENG_10, you need to upgrade to r346291 first
  (or older on RELENG_11, but we know r346291 works so recommend that)
  before upgrading to the latest on RELENG_11.  RELENG_10's
  static_assert implementation is used during bootstrapping with the new
  compiler, and turns out to be incompatible with the new compiler. It's
  unclear if this can be fixed easily but in the mean time add a note
  here.

Modified:
  stable/11/UPDATING

Modified: stable/11/UPDATING
==============================================================================
--- stable/11/UPDATING	Mon Jul  8 14:34:00 2019	(r349836)
+++ stable/11/UPDATING	Mon Jul  8 15:41:40 2019	(r349837)
@@ -25,8 +25,12 @@ from older version of current across the gcc/clang cut
 20190416:
 	Clang, llvm, lld, lldb, compiler-rt and libc++ have been upgraded to
 	8.0.0.  Please see the 20141231 entry below for information about
-	prerequisites and upgrading, if you are not already using clang 3.5.0
-	or higher.
+	prerequisites and upgrading, if you are not already using clang 3.5.0 or
+	higher. In addtion, if updating from RELENG_10, update to r346291 first,
+	then update to the most recent version of RELENG_11. The older
+	implementation of static_assert on RELENG_10 is incompatible with newer
+	compilers, so compilation errors will occur. The trick it uses to when
+	the builtin is unavailable now generates a fatal error.
 
 20190226:
 	geom_uzip(4) depends on the new module xz.  If geom_uzip is statically