Don't emit -Wxor-used-as-pow on macro expansions [PR107002]

Don't emit -Wxor-used-as-pow on macro expansions [PR107002]

PR c/107002 reports an assertion failure from deep inside the
diagnostic_shows_locus when attempting to print fix-it hints relating
to -Wxor-used-as-pow.  The case involves macro expansions with
-ftrack-macro-expansion=0.

It doesn't seem to make much sense to emit this warning for macro
expansions, so this patch updates the warning not to (which seems
to also be clang's behavior).  The patch also adds some bulletproofing
to diagnostic-show-locus.cc to be more robust against such invalid
fix-it hints.

Doing so fixes the ICE.

gcc/c-family/ChangeLog:
	PR c/107002
	* c-common.h (check_for_xor_used_as_pow): Add "rhs_loc" param.
	* c-warn.cc (check_for_xor_used_as_pow): Add "rhs_loc" param.
	Reject cases where involving macro expansions.

gcc/c/ChangeLog:
	PR c/107002
	* c-typeck.cc (parser_build_binary_op): Update for new param of
	check_for_xor_used_as_pow.

gcc/cp/ChangeLog:
	PR c/107002
	* parser.cc (cp_parser_binary_expression): Update for new param of
	check_for_xor_used_as_pow.

gcc/ChangeLog:
	PR c/107002
	* diagnostic-show-locus.cc (column_range::column_range): Factor
	out assertion conditional into...
	(column_range::valid_p): ...this new function.
	(line_corrections::add_hint): Don't attempt to consolidate hints
	if it would lead to invalid column_range instances.

gcc/testsuite/ChangeLog:
	PR c/107002
	* c-c++-common/Wxor-used-as-pow-1.c: Add macro test.
	* c-c++-common/Wxor-used-as-pow-pr107002-0.c: New test.
	* c-c++-common/Wxor-used-as-pow-pr107002-1.c: New test.
	* c-c++-common/Wxor-used-as-pow-pr107002-2.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>