bug#18302: MSYS2 build issues

[Eli Zaretskii]

> Date: Mon, 25 Aug 2014 10:18:20 +0200
> From: Karol Ostrovsky <karol.ostrovsky@gmail.com>
> Cc: Ken Brown <kbrown@cornell.edu>, Chris Zheng <chriszheng99@gmail.com>, 
> 18302@debbugs.gnu.org
> 
> As for the item 3: as far as I understand the
> situation with xpm in MinGW-w64 is the same as in Cygwin.  There are
> two packages providing xpm, and it is the package that is installed in
> the non-standard place that must be used for Emacs native Windows
> build.  Thus, I don't see why the same solution that was approved for
> Cygwin cannot be used for MinGW-w64.

I already said that IMO Cygwin should not add any switches, either.

In any case, the situation with MinGW-w64 is not the same as with
Cygwin: Cygwin has a version of xpm.h that is used with the X GUI and
another one that is used with the w32 GUI.  By contrast, MinGW-w64
doesn't support X, so it doesn't need to have 2 different headers by
the same name in the same include tree.

Did you try the alternative solution I suggested?  If not, please do:
I'm quite sure that it will work, and free you from the need to add
custom -I switches.