ubsan: Disable signed integer overflow sanitizer on GCC < 8

For opting functions out of sanitizer coverage, the "no_sanitize"
attribute is used, but in GCC this wasn't introduced until GCC 8.
Disable the sanitizer unless we're not using GCC, or it is GCC
version 8 or higher.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Reviewed-by: Marco Elver <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

Author: kees

lib/Kconfig.ubsan

@@ -119,6 +119,8 @@ config UBSAN_SIGNED_WRAP
 	bool "Perform checking for signed arithmetic wrap-around"
 	default UBSAN
 	depends on !COMPILE_TEST
+	# The no_sanitize attribute was introduced in GCC with version 8.
+	depends on !CC_IS_GCC || GCC_VERSION >= 80000
 	depends on $(cc-option,-fsanitize=signed-integer-overflow)
 	help
 	  This option enables -fsanitize=signed-integer-overflow which checks