builtins: use reserved spelling (NFC)
# ifdef COMPILER_RT_ARMHF_TARGET
# define COMPILER_RT_ABI
# else
-# define COMPILER_RT_ABI __attribute__((pcs("aapcs")))
+# define COMPILER_RT_ABI __attribute__((__pcs__("aapcs")))
# endif
#else
# define ARM_EABI_FNALIAS(aeabi_name, name)
