Re: MinGW compilation warnings in libiberty's waitpid.c

[Pedro Alves <palves@redhat.com>]

On 05/08/2017 04:27 PM, Eli Zaretskii wrote:
> When compiling libiberty (as part of GDB) with MinGW on MS-Windows, I
> see the following warning:
> 
>      gcc -c -DHAVE_CONFIG_H -O2 -gdwarf-4 -g3 -D__USE_MINGW_ACCESS  -I. -I./../include   -W -Wall -Wwrite-strings -Wc++-compat -Wstrict-prototypes -pedantic  -D_GNU_SOURCE ./waitpid.c -o waitpid.o
>      ./waitpid.c: In function 'waitpid':
>      ./waitpid.c:31:18: warning: implicit declaration of function 'wait' [-Wimplicit-function-declaration]
> 	    int wpid = wait(stat_loc);
> 		       ^
> 
> The file waitpid.c should not be built on MinGW, as it is not needed
> on Windows, and will not work if the function is called (because
> there's no 'wait' function on MS-Windows).
> 

Makes sense, but did you check whether there's an obvious place such
a change could be done in configure.ac?  

I wonder what code relies on this replacement, actually.  In liberty,
the only waitpid calls are in pex-unix.c, but those are all guarded
by HAVE_WAITPID.
Maybe it was used at some point when libiberty was a target library?

So I wonder whether we could just unconditionally remove the waitpid
replacement instead.

Thanks,
Pedro Alves