AC_MSG_WARN fix just checked in

[Jim Meyering]

FYI, I've just checked in the following fix.
Without it, code like this:

  test x = x || AC_MSG_WARN(foo)

would emit the warning to stderr (2nd stmt).

        * acgeneral.m4 (AC_MSG_WARN): Now that this macro expands to
        two stmts, enclose them in `{' ... `}'.

Index: acgeneral.m4
===================================================================
RCS file: /cvs/autoconf/acgeneral.m4,v
retrieving revision 1.596
diff -u -p -r1.596 acgeneral.m4
--- acgeneral.m4        2000/10/25 17:51:10     1.596
+++ acgeneral.m4        2000/10/29 19:41:21
@@ -2786,8 +2786,8 @@ _AC_ECHO_UNQUOTED([${ECHO_T}$1])[]dnl
 # AC_MSG_WARN(PROBLEM)
 # --------------------
 define([AC_MSG_WARN],
-[_AC_ECHO([configure:__oline__: WARNING: $1], AC_FD_LOG)
-_AC_ECHO([configure: WARNING: $1], 2)])
+[{ _AC_ECHO([configure:__oline__: WARNING: $1], AC_FD_LOG)
+_AC_ECHO([configure: WARNING: $1], 2); }])
 
 
 # AC_MSG_ERROR(ERROR, [EXIT-STATUS = 1])