3vtrasym.adb: Demangle Ada symbols returned by TBK$SYMBOLIZE.

3vtrasym.adb: Demangle Ada symbols returned by TBK$SYMBOLIZE.

	* 3vtrasym.adb:
	Demangle Ada symbols returned by TBK$SYMBOLIZE. Correctly align line
	numbers when symbol name is too long.

	* g-signal.ads, g-signal.adb: New files

	* impunit.adb: (Non_Imp_File_Names): Added "g-signal"

	* Makefile.rtl: Introduce GNAT.Signals

	* freeze.adb: Minor reformatting

	* lib-writ.adb (Write_ALI): Never write ali file if -gnats is specified

	* par.adb, par-ch12.adb, par-ch13.adb, par-ch2.adb, par-ch3.adb,
	par-ch5.adb, par-ch6.adb, par-ch9.adb, par-util.adb:
	New handling of Id_Check parameter to improve recognition of keywords
	used as identifiers.
	Update copyright notice to include 2003

From-SVN: r73083