mingw32.h: Make it explicit that we need XP or later.

mingw32.h: Make it explicit that we need XP or later.

2009-07-13  Vasiliy Fofanov  <fofanov@adacore.com>

	* mingw32.h: Make it explicit that we need XP or later.

	* initialize.c: Remove useless extern symbol declaration.

	* adaint.h: Ditto, also expose __gnat_win32_remove_handle to allow
	code reuse in expect.c.

	* adaint.c: Changes throughout the Windows section to redesign storage
	of the child process list and the process identification.

	* expect.c (__gnat_kill, __gnat_waitpid): Simplify, cleanup, use pids
	for interfacing, fix errors.
	(__gnat_expect_portable_execvp): use function in adaint.c

From-SVN: r149573