Add support for XOR

data/headers/windows/xor.h

@@ -0,0 +1,6 @@
+void xor(char* dest, char* src, char key, int len) {
+  for (int i = 0; i < len; i++) {
+    char c = src[i] ^ key;
+    dest[i] = c;
+  }
+}

lib/metasploit/framework/compiler/headers/windows.rb

@@ -22,7 +22,8 @@ module Metasploit
               'String.h'   => ['stddef.h'],
               'Winsock2.h' => ['stddef.h', 'Windows.h'],
               'rc4.h'      => ['String.h', 'stdlib.h'],
-              'base64.h'   => ['stddef.h']
+              'base64.h'   => ['stddef.h'],
+              'xor.h'      => ['stddef.h']
             }
           end