2008-03-26  Pascal Obry  <obry@adacore.com>

	* Makefile.in: Add proper GNAT.Serial_Communications implementation on
	supported platforms.
	
	* Makefile.rtl: Add g-sercom.o.
	
	* impunit.adb: Add g-sercom.adb.
	
	* s-crtl.ads (open): New routine.
	(close): Likewise.
	(write): Likewise.
	
	* s-osinte-mingw.ads (BYTE): New type.
	(CHAR): Likewise.
	(OVERLAPPED): Likewise.
	(GENERIC_READ): New constant.
	(GENERIC_WRITE): Likewise.
	(OPEN_EXISTING): Likewise.
	(PSECURITY_ATTRIBUTES): Removed this type, use anonymous access
	type instead.
	(CreateFile): New routine.
	(WriteFile): Likewise.
	(ReadFile): Likewise.
	(CloseHandle): Move next to the other file oriented routines.

	* g-sercom.ads: New unit.

	* g-sercom.adb: Default implementation, calls to this unit will raise
	a program error exception.
	
	* g-sercom-mingw.adb, g-sercom-linux.adb: Windows and
	GNU/Linux implementations.

From-SVN: r133569