configure: Provide the original toplevel configure arguments (including $0) to...

	* configure: Provide the original toplevel configure arguments
	(including $0) to subprocesses in the environment rather than
	through gcc/configargs.h.

gcc:
	* configure.in: Take toplevel configure arguments from the
	environment to create configargs.h and substitute
	gcc_config_arguments, taking account of any existing configargs.h
	if reconfiguring.
	* configure: Regenerate.
	* gccbug.in: Include toplevel configure arguments in gccbug.

From-SVN: r37423