re PR ada/52362 (gnat.dg/lto8.adb FAILs with gas/gld)

re PR ada/52362 (gnat.dg/lto8.adb FAILs with gas/gld)

	PR ada/52362
	* config.gcc (i[34567]86-*-mingw* | x86_64-*-mingw*): Set gas and
	gnu_ld variables to yes.
	* configure.ac (HAVE_GNU_LD): Move to after config.gcc inclusion.
	(HAVE_GNU_AS): Likewise.
	* config.in: Regenerate.
	* configure: Likewise.
ada/
	* link.c (__gnat_object_file_option): Set to "-Wl,@" for GNU linker.
	(__gnat_using_gnu_linker): Delete.
	* gnatlink.adb (Gnatlink): Declare Object_File_Option_Ptr here...
	Declare Object_File_Option string constant and Using_GNU_response_file
	boolean constant.
	(Process_Binder_File): ...instead of here.  Delete Using_GNU_Linker,
	Opening and Closing local variables.  Do not handle the GNU linker
	specially.
	(Write_RF): New procedure to write into the response file.  Escape some
	characters if a GNU response file is used.  Keep track of error status.
	Invoke Write_RF to write into the response file.  Delete the file only
	if the link was successful.
	* mlib-utl.adb: Do not `with' package System.
	(Gcc): Likewise.  Declare Object_File_Option string constant and
	Using_GNU_response_file boolean constant.
	(Write_RF): Take a string instead of address and length.  Escape some
	characters if a GNU response file is used.
	Invoke Write_RF to write into the response file.  Delete the file only
	if the link was successful.  Do not warn if it cannot be deleted.

From-SVN: r187874