Fix build.

The compilers had drifted a bit while I was away.

Change-Id: I938a5992e8e100f512db4c7934ac4b3ec80e8138
diff --git a/src/compiler/codegen/mips/MipsRallocUtil.cc b/src/compiler/codegen/mips/MipsRallocUtil.cc
index 22a19db..41bc991 100644
--- a/src/compiler/codegen/mips/MipsRallocUtil.cc
+++ b/src/compiler/codegen/mips/MipsRallocUtil.cc
@@ -151,6 +151,13 @@
     return res;
 }
 
+extern RegLocation oatGetReturnAlt(CompilationUnit* cUnit)
+{
+    UNIMPLEMENTED(FATAL);
+    RegLocation res = LOC_C_RETURN;
+    return res;
+}
+
 extern RegLocation oatGetReturn(CompilationUnit* cUnit)
 {
     RegLocation res = LOC_C_RETURN;