bootstrap: Fix some windows issues [PR 98300]

bootstrap: Fix some windows issues [PR 98300]

When breaking out the sample server from the gcc/cp directory, it lost
its check for mmap, and the sample resolver just assumed it was there.
Fixed thusly.  The non-mapping paths in module.cc weren't (recently)
excercised, and led to a signedness warning.  Finally I'd missed
c++tools's config.h.in in the gcc_update script.  There I took the
opportunity of adding a 'tools' segment of the dependency lists.

	PR bootstrap/98300
	contrib/
	* gcc_update: Add c++tools/config.h.in.
	c++tools/
	* configure.ac: Check for sys/mman.h.
	* resolver.cc: Don't assume mmap, O_CLOEXEC are available.  Use
	xmalloc.
	* config.h.in: Regenerated.
	* configure: Regenerated.
	gcc/cp/
	* module.cc: Fix ::read, ::write result signedness comparisons.