ubsan: Use Clang's -fsanitize-trap=undefined option

Clang changed the way it enables UBSan trapping mode. Update the Makefile
logic to discover it.

Suggested-by: Fangrui Song <[email protected]>
Link: https://lore.kernel.org/lkml/CAFP8O3JivZh+AAV7N90Nk7U2BHRNST6MRP0zHtfQ-Vj0m4+pDA@mail.gmail.com/
Reviewed-by: Fangrui Song <[email protected]>
Reviewed-by: Justin Stitt <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Nicolas Schier <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>

scripts/Makefile.ubsan

@@ -10,6 +10,6 @@ ubsan-cflags-$(CONFIG_UBSAN_DIV_ZERO)		+= -fsanitize=integer-divide-by-zero
 ubsan-cflags-$(CONFIG_UBSAN_UNREACHABLE)	+= -fsanitize=unreachable
 ubsan-cflags-$(CONFIG_UBSAN_BOOL)		+= -fsanitize=bool
 ubsan-cflags-$(CONFIG_UBSAN_ENUM)		+= -fsanitize=enum
-ubsan-cflags-$(CONFIG_UBSAN_TRAP)		+= -fsanitize-undefined-trap-on-error
+ubsan-cflags-$(CONFIG_UBSAN_TRAP)		+= $(call cc-option,-fsanitize-trap=undefined,-fsanitize-undefined-trap-on-error)
 
 export CFLAGS_UBSAN := $(ubsan-cflags-y)