zerosize_ptr mingw problems

[Simon Josefsson]

The zerosize_ptr stuff doesn't seem to work on MinGW:

rm -rf m; gnulib-tool --dir m --create-testdir --with-tests memchr; cd m; 
./configure --host=i586-mingw32msvc --build=i686-pc-linux-gnu ; make check

In file included from test-memchr.c:25:
zerosize-ptr.h:27:23: error: sys/mman.h: No such file or directory
In file included from test-memchr.c:25:
zerosize-ptr.h: In function ‘zerosize_ptr’:
zerosize-ptr.h:47: error: ‘MAP_PRIVATE’ undeclared (first use in this function)
zerosize-ptr.h:47: error: (Each undeclared identifier is reported only once
zerosize-ptr.h:47: error: for each function it appears in.)
zerosize-ptr.h:54: error: ‘PROT_READ’ undeclared (first use in this function)
zerosize-ptr.h:54: error: ‘PROT_WRITE’ undeclared (first use in this function)
zerosize-ptr.h:57: error: ‘PROT_NONE’ undeclared (first use in this function)
make[3]: *** [test-memchr.o] Error 1

/Simon