Add strigification for extruder amount in M115 report.

Marlin/language.h

 	#define FIRMWARE_URL "http://www.mendel-parts.com"
 #endif
 
+#define STRINGIFY_(n) #n
+#define STRINGIFY(n) STRINGIFY_(n)
+
 #if LANGUAGE_CHOICE == 1
 
 // LCD Menu Messages
 	#define MSG_HEATING_COMPLETE "Heating done."
 	#define MSG_BED_HEATING "Bed Heating."
 	#define MSG_BED_DONE "Bed done."
-	#define MSG_M115_REPORT "FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:" FIRMWARE_URL " PROTOCOL_VERSION:" PROTOCOL_VERSION " MACHINE_TYPE:" MACHINE_NAME " EXTRUDER_COUNT:1\n"
+	#define MSG_M115_REPORT "FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:" FIRMWARE_URL " PROTOCOL_VERSION:" PROTOCOL_VERSION " MACHINE_TYPE:" MACHINE_NAME " EXTRUDER_COUNT:" STRINGIFY(EXTRUDERS) "\n"
 	#define MSG_COUNT_X " Count X:"
 	#define MSG_ERR_KILLED "Printer halted. kill() called !!"
 	#define MSG_ERR_STOPPED "Printer stopped deu to errors. Fix the error and use M999 to restart!. (Temperature is reset. Set it before restarting)"
 	#define MSG_HEATING_COMPLETE "Heating done."
 	#define MSG_BED_HEATING "Bed Heating."
 	#define MSG_BED_DONE "Bed done."
-	#define MSG_M115_REPORT "FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:" FIRMWARE_URL " PROTOCOL_VERSION:" PROTOCOL_VERSION " MACHINE_TYPE:" MACHINE_NAME " EXTRUDER_COUNT:\n"
+	#define MSG_M115_REPORT "FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:" FIRMWARE_URL " PROTOCOL_VERSION:" PROTOCOL_VERSION " MACHINE_TYPE:" MACHINE_NAME " EXTRUDER_COUNT:" STRINGIFY(EXTRUDERS) "\n"
 	#define MSG_COUNT_X " Count X:"
 	#define MSG_ERR_KILLED "Printer halted. kill() called !!"
 	#define MSG_ERR_STOPPED "Printer stopped due to errors. Fix the error and use M999 to restart!"