* doc/tm.texi (TARGET_GET_PCH_VALIDITY, TARGET_PCH_VALID_P): Tweak
the documentation to make it more future-proof.
(TARGET_CHECK_PCH_TARGET_FLAGS): Document this new hook.
* target.h (gcc_target): Add check_pch_target_flags.
* target-def.h (TARGET_CHECK_PCH_TARGET_FLAGS): New macro.
(TARGET_INITIALIZER): Include it.
* toplev.c (default_pch_valid_p): Use targetm.check_pch_target_flags.
* config/sh/sh.h (sh_pch_valid_p): Delete.
* config/sh/sh.c (TARGET_PCH_VALID_P, sh_pch_valid_p): Delete.
(sh_check_pch_target_flags): New function.
(TARGET_CHECK_PCH_TARGET_FLAGS): Override default.
From-SVN: r100392
