re PR ada/83016 (gnat1: warning: command line option ‘-nostdinc++’ is valid for C++/ObjC++ but not for Ada)

	PR ada/83016
	* gnatlink.adb (Process_Args): Accept multiple switches for --LINK.
	(Usage): Adjust.
	* gcc-interface/Makefile.in (GCC_LINK): Remove $(ADA_INCLUDES).
	(common-tools): Pass $(CC) as --GCC= and $(GCC_LINK) as --LINK= in
	the invocations of $(GNATLINK).
	(../../gnatdll$(exeext)): Likewise.
	(../../vxaddr2line$(exeext)): Likewise.
	(gnatmake-re): Likewise.
	(gnatlink-re): Likewise.

From-SVN: r254940