initial support for Mega65 extra ROM

c64/basic/init/basic_cold_start_internal.s

@@ -1,8 +1,10 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_BASIC_0)
 
 //
 // Continuation of the BASIC cold start routine
 //
 
+
 basic_cold_start_internal:
 
 	// Setup vectors at $300
@@ -34,3 +36,6 @@ basic_cold_start_internal:
 
 	// jump into warm start loop
 	jmp basic_warm_start
+
+
+#endif // ROM layout