libobjc2 compile fail on MingW

[Adam Fedor]

I tried compiling the latest libobjc2 svn on MingW and got this:

This is gnustep-make 2.6.0. Type 'make print-gnustep-make-help' for help.
Making all for library libobjc...
 Compiling file block_to_imp.c ...
block_to_imp.c:8:22: fatal error: sys/mman.h: No such file or directory
compilation terminated.
make[3]: *** [obj/libobjc.obj/block_to_imp.c.o] Error 1
make[2]: *** [internal-library-all_] Error 2
make[1]: *** [libobjc.all.library.variables] Error 2
make: *** [internal-all] Error 2


Windows doesn't have mmap, but it can map files (see: 
http://sourceware.org/ml/binutils/2009-10/msg00169.html).  I'm not sure I 
understand enough about what libobjc2 is doing with mmap to implement a fix.