Re: OpenVMS needs __UNIX_PUTC macro defined for configure tests.

[Paul Eggert]

Bruno Haible wrote:
> I guess that this would not work:
>    #include <stdio.h>
>    #include "unlocked-io.h"
> would not make the unlocked IO routines visible, because <stdio.h> gets skipped
> when it gets included a second time. Right?

If we treat __UNIX_PUTC like we treat _GNU_SOURCE then we should be OK, since 
__UNIX_PUTC will be defined in config.h and thus the first <stdio.h> will see it.