Hi,

This patch implements target feature macros when PACBTI is
enabled through the -march option or -mbranch-protection.

Tested on arm-none-eabi. OK for trunk?

2021-10-04  Tejas Belagod  <tbelagod@arm.com>

gcc/ChangeLog:

	* config/arm/arm-c.c (arm_cpu_builtins): Define
	__ARM_FEATURE_BTI_DEFAULT and __ARM_FEATURE_PAC_DEFAULT.

gcc/testsuite/ChangeLog:

	* gcc.target/arm/acle/pacbti-m-predef-2.c: New test.
	* gcc.target/arm/acle/pacbti-m-predef-4.c: New test.
	* gcc.target/arm/acle/pacbti-m-predef-5.c: New test.