gcc/libmudflap: unavailable for gcc >= 4.9

Rework gcc dependency for mudflap as suggested by Arnout and Peter:
http://article.gmane.org/gmane.comp.lib.uclibc.buildroot/149813

libmudflap was removed in gcc 4.9:
https://gcc.gnu.org/wiki/Mudflap_Pointer_Debugging

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gcc/Config.in.host

@@ -151,9 +151,7 @@ config BR2_GCC_ENABLE_LIBMUDFLAP
 	# There are architectures, or specific configurations for
 	# which mudflap is not supported.
 	depends on !BR2_ARM_INSTRUCTIONS_THUMB && !BR2_powerpc_SPE
-	depends on !BR2_GCC_VERSION_4_9_X
-	depends on !BR2_GCC_VERSION_5_X
-	depends on !BR2_GCC_VERSION_6_X
+	depends on !BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
 	help
 	  libmudflap is a gcc library used for the mudflap pointer
 	  debugging functionality. It is only needed if you intend to