testsuite: Fix up testsuite/gcc.c-torture/execute/builtins/lib/chk.c for powerpc...

testsuite: Fix up testsuite/gcc.c-torture/execute/builtins/lib/chk.c for powerpc [PR104380]

> > The following testcase FAILs when configured with
> > --with-long-double-format=ieee .  Only happens in the -std=c* modes, not the
> > GNU modes; while the glibc headers have __asm redirects of
> > vsnprintf and __vsnprinf_chk to __vsnprintfieee128 and
> > __vsnprintf_chkieee128, the vsnprintf fortification extern inline gnu_inline
> > always_inline wrapper calls __builtin_vsnprintf_chk and we actually emit
> > a call to __vsnprinf_chk (i.e. with IBM extended long double) instead of
> > __vsnprintf_chkieee128.
> >
> > rs6000_mangle_decl_assembler_name already had cases for *printf and *scanf,
> > so this just adds another case for *printf_chk.  *scanf_chk doesn't exist.
> > __ prefixing isn't done because *printf_chk already starts with __.

Unfortunately, while I've tested the testcase also with -mabi=ieeelongdouble
by hand, the full bootstrap/regtest was on GCCFarm where glibc is too old
to test with --with-long-double-format=ieee.
I've done full bootstrap/regtest with that option during the weekend and
the patch regressed:
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O1
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O2
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O2 -flto -fno-use-linker-plugin -flto-partition=none
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -O3 -g
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -Og -g
FAIL: gcc.c-torture/execute/builtins/snprintf-chk.c execution,  -Os
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O1
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O2
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O2 -flto -fno-use-linker-plugin -flto-partition=none
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -O3 -g
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -Og -g
FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution,  -Os
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O1
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O2
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O2 -flto -fno-use-linker-plugin -flto-partition=none
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O3 -g
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -Og -g
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -Os
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O1
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O2
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O2 -flto -fno-use-linker-plugin -flto-partition=none
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -O3 -g
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -Og -g
FAIL: gcc.c-torture/execute/builtins/vsprintf-chk.c execution,  -Os

The problem is that the execute/builtins/ testsuite wants to override some
of the library functions and with the change we (correctly) call
__*printf_chkieee128 and so lib/chk.c is no longer called but the glibc
APIs are.

2022-02-07  Jakub Jelinek  <jakub@redhat.com>

	PR target/104380
	* gcc.c-torture/execute/builtins/lib/chk.c (__sprintf_chkieee128,
	__vsprintf_chkieee128, __snprintf_chkieee128,
	__vsnprintf_chkieee128): New aliases to non-ieee128 suffixed functions
	for powerpc -mabi=ieeelongdouble.