Fix the sanity-check for config versions

Marlin/src/inc/SanityCheck.h

  * the bleeding-edge source code, but sometimes this is not enough. This check
  * forces a minimum config file revision. Otherwise Marlin will not build.
  */
-#if !defined(CONFIGURATION_H_VERSION) || CONFIGURATION_H_VERSION < REQUIRED_CONFIGURATION_H_VERSION
+#define HEXIFY(H) _CAT(0x,H)
+#if !defined(CONFIGURATION_H_VERSION) || HEXIFY(CONFIGURATION_H_VERSION) < HEXIFY(REQUIRED_CONFIGURATION_H_VERSION)
   #error "You are using an old Configuration.h file, update it before building Marlin."
 #endif
 
-#if !defined(CONFIGURATION_ADV_H_VERSION) || CONFIGURATION_ADV_H_VERSION < REQUIRED_CONFIGURATION_ADV_H_VERSION
+#if !defined(CONFIGURATION_ADV_H_VERSION) || HEXIFY(CONFIGURATION_ADV_H_VERSION) < HEXIFY(REQUIRED_CONFIGURATION_ADV_H_VERSION)
   #error "You are using an old Configuration_adv.h file, update it before building Marlin."
 #endif