bug#19874: 25.0.50; encode-time not working as expected

[Wolfgang Jenkner]

On Thu, Feb 26 2015, Paul Eggert wrote:

> Emacs's putenv implementation should be portable to any POSIX
> platform, but FreeBSD 10.1 getenv+setenv has a bug.  The attached
> program should work on any POSIX platform, and it does work on
> GNU/Linux and on Solaris, but it doesn't work on FreeBSD 10.1.  Emacs
> has similar code, which apparently also runs afoul of the FreeBSD bug.
>
> #include <stdio.h>
> #include <stdlib.h>
> extern char **environ;
> char env1[] = "abc=def";
> char *small_environ[] = { env1, 0 };
> int
> main (void)
> {
>   environ = small_environ;
>   if (setenv ("mno", "pqr", 0) != 0)
>     return perror ("setenv"), 1;
>   env1[0] = 'x';
>   if (! getenv ("xbc"))
>     return fprintf (stderr, "getenv failed\n"), 1;
>   return 0;
> }

IIUC, the standard explicitly permits the FreeBSD behaviour, so the
program above does not seem to be conforming:

http://pubs.opengroup.org/onlinepubs/9699919799/functions/getenv.html

        If the application switches to a complete new environment by
        assigning a new value to environ, this can be detected by
        getenv(), setenv(), unsetenv(), or putenv() and the
        implementation can at that point reinitialize based on the new
        environment. (This may include copying the environment strings
        into a new array and assigning environ to point to it.)