re PR testsuite/25352 (xfail within dg-do command has no effect)

re PR testsuite/25352 (xfail within dg-do command has no effect)

gcc/
	PR testsuite/25352
	* doc/sourcebuild.texi (Test Directives): Document that xfail
	has no effect for dg-do except when dg-do-what is "run".

libstdc++-v3/
	PR testsuite/25352
	* testsuite/26_numerics/headers/cmath/c99_classification_macros_c.cc:
	Remove xfail from dg-do and add dg-skip-if.

gcc/testsuite/
	PR testsuite/25352
	* gcc.c-torture/compile/20000804-1.c: Remove xfail from dg-do and
	add dg-skip-if.
	* gcc.c-torture/compile/20001205-1.c: Ditto.
	* gcc.c-torture/compile/20001226-1.c: Ditto.
	* gcc.c-torture/compile/20020312-1.c: Ditto.
	* gcc.c-torture/compile/20020604-1.c: Ditto.
	* gcc.c-torture/compile/920501-12.c: Ditto.
	* gcc.c-torture/compile/920501-4.c: Ditto.
	* gcc.c-torture/compile/920520-1.c: Ditto.
	* gcc.c-torture/compile/980506-1.c: Ditto.
	* gcc.c-torture/compile/990617-1.c: Ditto.
	* gcc.dg/compare6.c: Ditto.
	* g++.old-deja/g++.brendan/crash43.C: Ditto.
	* g++.old-deja/g++.brendan/synth1.C: Ditto.
	* g++.old-deja/g++.oliva/dwarf2.C: Ditto.
	* g++.old-deja/g++.oliva/dwarf3.C: Ditto.
	* g++.old-deja/g++.pt/static6.C: Ditto.
	* g++.old-deja/g++.pt/crash16.C: Ditto.
	* g++.old-deja/g++.mike/p10416.C: Ditto.
	* g++.old-deja/g++.mike/ns15.C: Ditto.
	* g++.old-deja/g++.mike/eh46.C: Ditto.

From-SVN: r129823