bug#7848: 23.2.91; Can't build with MinGW

[Kazuhiro Ito]

When I build emacs-23 branch at present with MinGW, below error
occurs while linking.

> oo-spd/i386/temacs1.a(image.o):image.c:(.text+0xa8fa): undefined reference to 
> `SET_SYMBOL_VAL'
> collect2: ld returned 1 exit status
> make[1]: *** [oo-spd/i386/temacs.exe] Error 1
> make[1]: Leaving directory `/f/build/emacs-23/src'
> make: *** [all-other-dirs-gmake] Error 2

SET_SYMBOL_VAL is defined in src/lisp.h on trunk but not on emacs-23
branch.

-- 
Kazuhiro Ito