resolve merge conflicts of 602859b18603fea642cbcd486563f6bfa981eb4d to rvc-d1-dev am: 3d723c29d1 am: 0d0d422359 am: 35e0e89aa7

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/12735596

Change-Id: Ia83973413013c469231d28de0023dc516ca725ca
diff --git a/core/rbe.mk b/core/rbe.mk
index 91606d4..19c0e42 100644
--- a/core/rbe.mk
+++ b/core/rbe.mk
@@ -34,6 +34,12 @@
     cxx_compare := false
   endif
 
+  ifdef RBE_CXX_COMPARE
+    cxx_compare := $(RBE_CXX_COMPARE)
+  else
+    cxx_compare := "false"
+  endif
+
   ifdef RBE_JAVAC_EXEC_STRATEGY
     javac_exec_strategy := $(RBE_JAVAC_EXEC_STRATEGY)
   else