fixincludes: Bypass solaris_math_12 on newer Solaris 11.4

Solaris 11 <math.h> long had this snippet

which badly broke libstdc++.  This has long been undone using
fixincludes in

	[fixincludes, v3] Don't define libstdc++-internal macros in Solaris 10+ <math.h>
	https://gcc.gnu.org/ml/gcc-patches/2016-11/msg00330.html

However, the issue came up again recently when that code broke the LLVM
build, too, which unfortunately doesn't know about GCC's include-fixed
directory.  The issue was reinvestigated and it turned out that the
workaround/hack is only needed for specific old versions of the Sun/Oracle
Studio compilers.  So <math.h> now looks like

/* Accommodate historical C++11 -std=c++03 behavior of Studio 12.4 and 12.5 */
    ((__SUNPRO_CC == 0x5130) || (__SUNPRO_CC == 0x5140) ||  \
     defined(__MATH_PREEMPTS_GLIBCXX_C99_MATH))

If this change is in place, there's no longer a need for the fixincludes
fix, so this patch bypasses it as appropriate.

Tested on Solaris 11.3 (without the fixed header) and recent 11.4 (with
the fixed header).

2022-11-01  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	fixincludes:
	* inclhack.def (solaris_math_12): Add bypass.
	* fixincl.x: Regenerate.