Re: uint64_t fails with C++

[Paul Eggert]

Thanks for the details.  I pushed this patch
into autoconf:

AC_LANG_BOOL_COMPILE_TRY(C): port to g++ with warnings
* lib/autoconf/c.m4 (AC_LANG_BOOL_COMPILE_TRY(C)): Use the
array as well as setting it, to pacify g++.  Reported by
Werner Lemberg in
<http://lists.gnu.org/archive/html/autoconf/2011-12/msg00005.html>.
diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 88785d1..0fdf9dd 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -190,7 +190,8 @@ choke me
 # errors with `-W error'.
 m4_define([AC_LANG_BOOL_COMPILE_TRY(C)],
 [AC_LANG_PROGRAM([$1], [static int test_array @<:@1 - 2 * !($2)@:>@;
-test_array @<:@0@:>@ = 0
+test_array @<:@0@:>@ = 0;
+return test_array @<:@0@:>@;
 ])])