Mention new AC_DEFUN_ONCE clients.

* NEWS: Mention recent semantic changes.
Reported by Ralf Wildenhues.

Signed-off-by: Eric Blake <ebb9@byu.net>

diff --git a/ChangeLog b/ChangeLog
index 67b207ce7316f4da0c52f5e04d952c2c660eea97..c72253ab0a28fb2a304acbff4c8758127a7d4e04 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-02-05  Eric Blake  <ebb9@byu.net>
+
+       Mention new AC_DEFUN_ONCE clients.
+       * NEWS: Mention recent semantic changes.
+       Reported by Ralf Wildenhues.
+
 2009-02-03  Eric Blake  <ebb9@byu.net>
 
        Use AC_DEFUN_ONCE for some one-shot AC_PROG macros.

diff --git a/NEWS b/NEWS
index ba006cd8fa3214a99e7f08e07207c8cb0acfba16..94b310e34796b4a0e631b723994d3833a0c1a38e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -20,6 +20,16 @@ GNU Autoconf NEWS - User visible changes.
    and subsequent invocations are a silent no-op.  This makes
    AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
 
+** The following macros are now defined with AC_DEFUN_ONCE.  This means
+   a subtle change in semantics; previously, an AC_DEFUN macro could
+   expand one of these macros multiple times or surround the macro
+   inside shell conditional text to bypass the effects of these
+   macros, but now the macro will expand exactly once, and prior to
+   the start of any enclosing AC_DEFUN macro:
+   AC_CANONICAL_BUILD  AC_CANONICAL_HOST  AC_CANONICAL_TARGET
+   AC_HEADER_ASSERT  AC_PROG_INSTALL  AC_PROG_MKDIR_P
+   AC_USE_SYSTEM_EXTENSIONS
+
 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
 
 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no