Re: Building latest on Windows: error in unistd.h

[Eli Zaretskii <eliz@gnu.org>]

> From: Gary Oberbrunner <garyo@oberbrunner.com>
> Date: Wed, 22 Sep 2021 13:01:22 -0400
> 
> I just updated to the latest master (eb42c4b099c171) and did make bootstrap in my mingw64 terminal
> (Windows 10), but I get the following  "Please include config.h first" error:
> 
> make[2]: Entering directory '/c/Users/garyo/src/emacs/emacs/lib-src'
>   CC       ntlib.o
> In file included from ../lib/time.h:44,
>                  from ntlib.c:26:
> ../lib/unistd.h:660:3: error: #error "Please include config.h first."
>   660 |  #error "Please include config.h first."
>       |   ^~~~~
> ../lib/unistd.h:662:24: error: expected ';' before 'extern'
>   662 | _GL_INLINE_HEADER_BEGIN
>       |                        ^
>       |                        ;
> In file included from ../lib/time.h:47,
>                  from ntlib.c:26:
> C:/msys64/mingw64/x86_64-w64-mingw32/include/time.h:24:9: error: expected '=', ',', ';', 'asm' or
> '__attribute__' before '#pragma'
>    24 | #pragma pack(push,_CRT_PACKING)
>       |         ^~~~
> make[2]: *** [Makefile:418: ntlib.o] Error 1
> 
> My configure line looks like this:
> 
> ./configure --with-jpeg --with-xpm --with-png --with-tiff --with-rsvg --with-xml2 --with-gnutls
> --without-imagemagick --prefix=c:/emacs/emacs-trunk-2021
> 
> Something missing/misconfigured on my end I guess?

How come lib/unistd.h is at all generated and used in your MinGW
build?  It isn't supposed to be, we use unistd.h that comes with
MinGW.

Please try to figure out why configure decided to generate
lib/unistd.h.  Crystal ball says you updated your MinGW64 headers not
long ago, and something there causes that.