add xbox patch support

system/client-functions/VersionDetectXB.x86.s

@@ -0,0 +1,18 @@
+# This function returns the game version, with values more specific than can be
+# detected by the sub_version field in the various login commands (e.g. 9D/9E).
+
+# The returned value has the format SSSSRRVV, where:
+#   S = 344F (which represents PSO Xbox)
+#   R = region (45 (E), 4A (J), or 50 (P))
+#   V = version (42 (B) for beta, 44 (D) for disc, 55 (U) for title update)
+# This results in a 4-character ASCII-printable version code which encodes all
+# of the above information. This value is called specific_version in the places
+# where it's used by the server.
+
+entry_ptr:
+reloc0:
+  .offsetof start
+
+start:
+  .include VersionDetectWithPatchFunctionsXB
+  ret