toolchain/Config.in: add BR2_TOOLCHAIN_GCC_AT_LEAST_12 blind option

In order to add gcc 12 support for internal and external toolchain
in follow-up commits, introduce BR2_TOOLCHAIN_GCC_AT_LEAST_12 symbol.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

toolchain/Config.in

@@ -117,7 +117,8 @@ config BR2_TOOLCHAIN_HAS_GCC_BUG_43744
 	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_8 || \
 		BR2_TOOLCHAIN_GCC_AT_LEAST_9 || \
 		BR2_TOOLCHAIN_GCC_AT_LEAST_10 || \
-		BR2_TOOLCHAIN_GCC_AT_LEAST_11
+		BR2_TOOLCHAIN_GCC_AT_LEAST_11 || \
+		BR2_TOOLCHAIN_GCC_AT_LEAST_12
 
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63261. This bug no
 # longer exists in gcc 8.x.
@@ -150,7 +151,8 @@ config BR2_TOOLCHAIN_HAS_GCC_BUG_68485
 config BR2_TOOLCHAIN_HAS_GCC_BUG_83143
 	bool
 	default y if BR2_sh
-	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_10 || BR2_TOOLCHAIN_GCC_AT_LEAST_11
+	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_10 || BR2_TOOLCHAIN_GCC_AT_LEAST_11 || \
+		   BR2_TOOLCHAIN_GCC_AT_LEAST_12
 
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85180. This bug no
 # longer exists in gcc 8.x.
@@ -698,10 +700,15 @@ config BR2_TOOLCHAIN_GCC_AT_LEAST_11
 	bool
 	select BR2_TOOLCHAIN_GCC_AT_LEAST_10
 
+config BR2_TOOLCHAIN_GCC_AT_LEAST_12
+	bool
+	select BR2_TOOLCHAIN_GCC_AT_LEAST_11
+
 # This order guarantees that the highest version is set, as kconfig
 # stops affecting a value on the first matching default.
 config BR2_TOOLCHAIN_GCC_AT_LEAST
 	string
+	default "12"	if BR2_TOOLCHAIN_GCC_AT_LEAST_12
 	default "11"	if BR2_TOOLCHAIN_GCC_AT_LEAST_11
 	default "10"	if BR2_TOOLCHAIN_GCC_AT_LEAST_10
 	default "9"	if BR2_TOOLCHAIN_GCC_AT_LEAST_9