gnulib problem with mktime & ctime interaction

[Ross McFarland]

when using gnulib's mktime test any cpp file that #includes ctime will
receive the following errors:

In file included from time.cc:6:
/usr/include/c++/4.3/ctime:73: error: ‘::mktime’ has not been declared
time.cc: In function ‘int main()’:
time.cc:11: error: ‘mktime’ was not declared in this scope

this happens on both Ubuntu 9.04 and FreeBSD 7.1. it was discovered
when trying to port drizzle to FreeBSD and testing with the minimal
test-case showed the same problem on linux. the problem is more
prevelant on FreeBSD because ctime is #included by other systems
headers, but it would affect any cpp program trying to use the mktime
test and ctime on linux/ubuntu as well.

the problem is that ctime does the following:

...
#include <time.h>
...
#undef mktime
...
using ::mktime
...

the undef mktime gets rid of the config.h mapping of mktime to
rpl_mktime and when using ::mktime happens there's no longer a mktime
symbol.

attached is a ~minimal test program that exhibits the problem. so far
i've only found work-arounds that remove the mktime.m4 behavior and
thus are undesirable.

animal$ uname -a
Linux animal 2.6.28-13-generic #45-Ubuntu SMP Tue Jun 30 22:12:12 UTC
2009 x86_64 GNU/Linux
animal$ gcc --version
gcc (Ubuntu 4.3.3-5ubuntu4) 4.3.3
Copyright (C) 2008 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

ralph$ uname -a
FreeBSD ralph.local 7.1-RELEASE FreeBSD 7.1-RELEASE #0: Thu Jan  1
08:58:24 UTC 2009
address@hidden:/usr/obj/usr/src/sys/GENERIC  amd64
ralph$ gcc --version
gcc (GCC) 4.2.1 20070719  [FreeBSD]
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

thoughts?

best,
--
-rm

gnulib-mktime-bug.tar.gz
Description: GNU Zip compressed data