re PR bootstrap/71400 (profiledbootstrap failed)

	PR libgcc/71400
	* libgcov-driver-system.c (__gcov_error_file): Disable if IN_GCOV_TOOL.
	(get_gcov_error_file): Check __gcov_error_file before trying to
	initialize it.
	(gcov_error): Always use get_gcov_error_file.

Co-Authored-By: Nathan Sidwell <nathan@acm.org>

From-SVN: r237135