Preliminary changes to allow mips target to build.

It compiles, but it doesn't work yet.

Change-Id: I2973a03bd956d8d398b9cfd1047e66fbf3ff439c
diff --git a/src/oat/utils/assembler.h b/src/oat/utils/assembler.h
index 68108e7..a1e3914 100644
--- a/src/oat/utils/assembler.h
+++ b/src/oat/utils/assembler.h
@@ -20,6 +20,7 @@
 #include <vector>
 
 #include "constants_arm.h"
+#include "constants_mips.h"
 #include "constants_x86.h"
 #include "instruction_set.h"
 #include "logging.h"
@@ -37,6 +38,9 @@
 namespace arm {
   class ArmAssembler;
 }
+namespace mips {
+  class MipsAssembler;
+}
 namespace x86 {
   class X86Assembler;
 }
@@ -86,6 +90,7 @@
   }
 
   friend class arm::ArmAssembler;
+  friend class mips::MipsAssembler;
   friend class x86::X86Assembler;
 
   DISALLOW_COPY_AND_ASSIGN(Label);