Hi,

Recently if we build gcc on Power with the assembler which doesn't
have Power10 support, the build will fail when building libgcc with
one error message like:

Error: invalid switch -mpower10
Error: unrecognized option -mpower10
make[2]: *** [...gcc/gcc-base/libgcc/shared-object.mk:14: float128-p10.o] Error 1

By checking the culprit commit r12-1340, it's caused by some typos.

What the proposed patch does:
  - fix test target typo libgcc_cv_powerpc_3_1_float128_hw
    (written wrongly as libgcc_cv_powerpc_float128_hw, so it's going
     to build ISA3.1 stuffs just when detecting ISA3.0).
  - fix test case used for libgcc_cv_powerpc_3_1_float128_hw check.
  - fix test option used for libgcc_cv_powerpc_3_1_float128_hw check.
  - remove the ISA3.1 related contents from t-float128-hw.
  - add new macro FLOAT128_HW_INSNS_ISA3_1 to differentiate ISA3.1
    content from ISA3.0 part in ifunc support.

For the last two points, I think it's by design, when the assembler
only supports power9 insns but not power10 insns, we are unable to
build power10 hw supported function successfully, so we shouldn't
generate related ifunc stuffs which rely on p10 insns.

This patch makes the build happy even without p10 supported as.

Bootstrapped/regtested on:
  - powerpc64le-linux-gnu P10
  - powerpc64le-linux-gnu P9 (w/i and w/o p10 supported as)
  - powerpc64-linux-gnu P8 (w/i and w/o p10 supported as)

BTW, there are some noises during regression testings due to
newer versions binutils, but they were identified as unrelated
after some checkings.

Is it ok for trunk?

BR,
Kewen
-----
libgcc/ChangeLog:

	* configure: Regenerate.
	* configure.ac (test for libgcc_cv_powerpc_3_1_float128_hw): Fix
	typos among name, CFLAGS and test case.
	* config/rs6000/t-float128-hw(fp128_3_1_hw_funcs,
	fp128_3_1_hw_src, fp128_3_1_hw_static_obj, fp128_3_1_hw_shared_obj,
	fp128_3_1_hw_obj): Remove variables for ISA 3.1 support.
	* config/rs6000/t-float128-p10-hw (FLOAT128_HW_INSNS): Append
	macro FLOAT128_HW_INSNS_ISA3_1 for ISA 3.1 support.
	(FP128_3_1_CFLAGS_HW): Fix option typo.
	* config/rs6000/float128-ifunc.c (SW_OR_HW_ISA3_1): Guarded
	with FLOAT128_HW_INSNS_ISA3_1.
	(__floattikf_resolve): Likewise.
	(__floatuntikf_resolve): Likewise.
	(__fixkfti_resolve): Likewise.
	(__fixunskfti_resolve): Likewise.
	(__floattikf): Likewise.
	(__floatuntikf): Likewise.
	(__fixkfti): Likewise.
	(__fixunskfti): Likewise.