ppc: add support for clang target attribute
* configure.ac (gcry_cv_clang_attribute_ppc_target): New. * cipher/chacha20-ppc.c [HAVE_CLANG_ATTRIBUTE_PPC_TARGET] (FUNC_ATTR_TARGET_P8, FUNC_ATTR_TARGET_P9): New. * cipher/rijndael-ppc.c [HAVE_CLANG_ATTRIBUTE_PPC_TARGET] (FPC_OPT_ATTR): New. * cipher/rijndael-ppc9le.c [HAVE_CLANG_ATTRIBUTE_PPC_TARGET] (FPC_OPT_ATTR): New. * cipher/sha256-ppc.c [HAVE_CLANG_ATTRIBUTE_PPC_TARGET] (FUNC_ATTR_TARGET_P8, FUNC_ATTR_TARGET_P9): New. * cipher/sha512-ppc.c [HAVE_CLANG_ATTRIBUTE_PPC_TARGET] (FUNC_ATTR_TARGET_P8, FUNC_ATTR_TARGET_P9): New. (ror64): Remove unused function.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>