Add TARGET_LOWER_LOCAL_DECL_ALIGNMENT [PR95237]

Add TARGET_LOWER_LOCAL_DECL_ALIGNMENT [PR95237]

Default for this hook is NOP. For x86, in 32 bit mode, this hook
sets alignment of long long on stack to 32 bits if preferred stack
boundary is 32 bits.

  - This patch prevents lowering of alignment from following macros.
	LOCAL_ALIGNMENT
	STACK_SLOT_ALIGNMENT
	LOCAL_DECL_ALIGNMENT
  - This patch fixes
	gcc.target/i386/pr69454-2.c
	gcc.target/i386/stackalign/longlong-1.c
  - Regression test on x86-64, no new fail introduced.

Tested on x86-64.

gcc/c/ChangeLog:

	PR target/95237
	* c-decl.c (finish_decl): Call target hook
	lower_local_decl_alignment to lower local decl alignment.

gcc/ChangeLog:

	PR target/95237
	* config/i386/i386-protos.h (ix86_local_alignment): Add
	another function parameter may_lower alignment. Default is
	false.
	* config/i386/i386.c (ix86_lower_local_decl_alignment): New
	function.
	(ix86_local_alignment): Amend ix86_local_alignment to accept
	another parameter may_lower. If may_lower is true, new align
	may be lower than incoming alignment. If may_lower is false,
	new align will be greater or equal to incoming alignment.
	(TARGET_LOWER_LOCAL_DECL_ALIGNMENT): Define.
	* doc/tm.texi: Regenerate.
	* doc/tm.texi.in (TARGET_LOWER_LOCAL_DECL_ALIGNMENT): New
	hook.
	* target.def (lower_local_decl_alignment): New hook.

gcc/cp/ChangeLog:

	PR target/95237
	* decl.c (cp_finish_decl): Call target hook
	lower_local_decl_alignment to lower local decl alignment.

gcc/testsuite/ChangeLog:

	PR target/95237
	* c-c++-common/pr95237-1.c: New test.
	* c-c++-common/pr95237-2.c: New test.
	* c-c++-common/pr95237-3.c: New test.
	* c-c++-common/pr95237-4.c: New test.
	* c-c++-common/pr95237-5.c: New test.
	* c-c++-common/pr95237-6.c: New test.
	* c-c++-common/pr95237-7.c: New test.
	* c-c++-common/pr95237-8.c: New test.
	* c-c++-common/pr95237-9.c: New test.