bug#17673: 24.4.50; trunk r117239 build failure on Windows

[Andy Moreton]

Building trunk r117239 with mingw32 fails:

gcc -std=gnu99  -c -mtune=pentium4   -I/c/emacs/mingw-devel/include 
-I/c/emacs/mingw-devel/src/xpm/3.5.1/libXpm-3.5.1-src/lib 
-DUSE_CRT_DLL=1 -I /c/emacs/src/emacs/trunk/obj-mingw32/../nt/inc 
-Demacs  -I. -I../../src -I../lib -I../../src/../lib -DHEAPSIZE=12 
-mtune=pentium4    -mms-bitfields 
-Ic:/emacs/mingw-devel/include/librsvg-2.0 
-Ic:/emacs/mingw-devel/include/glib-2.0 
-Ic:/emacs/mingw-devel/lib/glib-2.0/include 
-Ic:/emacs/mingw-devel/include/gdk-pixbuf-2.0 
-Ic:/emacs/mingw-devel/include/cairo 
-Ic:/emacs/mingw-devel/include/libpng16 
-Ic:/emacs/mingw-devel/include/pixman-1 
-Ic:/emacs/mingw-devel/include/libxml2            -MMD -MF deps/menu.d 
-MP -Ic:/emacs/mingw-devel/include 
-Ic:/emacs/mingw-devel/include/p11-kit-1      -O0 -g3  ../../src/menu.c
In file included from ../../src/menu.h:25:0,
                 from ../../src/menu.c:52:
../../src/../lwlib/lwlib.h:24:27: fatal error: X11/Intrinsic.h: No such 
file or directory
compilation terminated.
make[1]: *** [menu.o] Error 1

Trunk builds on mingw32 with r117238.

    AndyM