bug#51583: 29.0.50; cygw32 build break

[Eli Zaretskii]

> Date: Wed, 03 Nov 2021 20:35:57 +0900
> From: Kazuhiro Ito <kzhr@d1.dion.ne.jp>
> 
> Cygw32 build fails on trunk.
> 
> $ ./configure --with-w32
> $ make
> 
> (snip)
>   CCLD     temacs.exe
> /usr/lib/gcc/x86_64-pc-cygwin/10/../../../../x86_64-pc-cygwin/bin/ld: 
> w32fns.o:w32fns.c:(.text+0xec1a): undefined reference to `w32_get_resource'
> collect2: error: ld returned 1 exit status
> make[1]: *** [Makefile:647: temacs.exe] Error 1
> make[1]: Leaving directory '/dfs/f/build/cygwin64/emacs/src'
> make: *** [Makefile:450: src] Error 2
> 
> w32_get_resource function is defined in w32.c, which is not compiled
> on Cygwin buid.

Thanks, I tried to fix this now.  Please test, including the new
dark-theme functionality (if you have a new enough Windows
installation).