Re: Build failure in gettimeofday

[Eli Zaretskii <eliz@gnu.org>]

> Cc: emacs-devel@gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Wed, 16 Sep 2020 10:21:56 +0200
> 
> Thank you.  A -O0 -g3 build succeeds now but a -O3 build currently
> fails thusly:
> 
> In file included from ../../src/emacs.c:68:0:
> ../../src/bignum.h:25:17: fatal error: gmp.h: No such file or directory
>   #include <gmp.h>
>                   ^
> compilation terminated.
> make[1]: *** [emacs.o] Error 1

??? How did the -O0 build get past this problem?  Header file
inclusion doesn't depend on optimizations.  Are you sure you have a
clean working tree, devoid of stale object files?

Anyway, it sounds like you don't have GMP installed?  In that case,
running configure is supposed to create lib/gmp.h, and the above
inclusion in bignum.h is supposed to find it.  It works for me on a
system where there's no libgmp.  Do you have lib/gmp.h?  If you do,
then perhaps this is a compiler bug: it should be able to find that
file, because the compiler switches include "-I../lib".

If you don't have lib/gmp.h, then your tree is mis-configured somehow.

Or maybe this is another aspect of our less-than-ideal support for
out-of-tree builds.

> but I doubt that these can be relevant.  Any clues?  A couple of
> warnings from the -O0 build just in case they could hint at anything.
> 
>    CC       menu.o
> ../../src/xdisp.c: In function 'move_it_in_display_line_to':
> ../../src/xdisp.c:9557:10: warning: unknown conversion type character 't' in format [-Wformat=]
>            IT_CHARPOS (*it));
>            ^
> ../../src/xdisp.c:9557:10: warning: too many arguments for format [-Wformat-extra-args]
> ../../src/xdisp.c: In function 'move_it_to':
> ../../src/xdisp.c:9925:8: warning: unknown conversion type character 't' in format [-Wformat=]
>          move_trace ("move_it: from %td\n", IT_CHARPOS (*it));
>          ^
> ../../src/xdisp.c:9925:8: warning: too many arguments for format [-Wformat-extra-args]
> ../../src/xdisp.c:9928:8: warning: unknown conversion type character 't' in format [-Wformat=]

That's because of your ancient version of GCC.  You will have to live
with this.

> ../../src/data.c: In function 'bignum_arith_driver':
> ../../src/data.c:2821:9: warning: assignment from incompatible pointer type [enabled by default]
>     accum = &mpz[0];
>           ^
> ../../src/data.c:2843:13: warning: assignment from incompatible pointer type [enabled by default]
>         accum = &mpz[0];
>               ^

That's the usual noise with GCC 4.x when compiling mini-gmp.  I
reported this as a bug, but no one wants to fix it, so I guess us
providing mini-gmp is just a lip service, and you are advised to
install libgmp if you are annoyed enough by these warnings.