Fix ARM build on mac.

src/arm/regexp-macro-assembler-arm.h

Index: src/arm/regexp-macro-assembler-arm.h
diff --git a/src/arm/regexp-macro-assembler-arm.h b/src/arm/regexp-macro-assembler-arm.h
index 9f07489e1fc4d63ca8238e6ea03430a699e90188..8d9d515c76b2123f74eeb5c6d65f386263c27504 100644
--- a/src/arm/regexp-macro-assembler-arm.h
+++ b/src/arm/regexp-macro-assembler-arm.h
@@ -223,11 +223,6 @@ class RegExpMacroAssemblerARM: public NativeRegExpMacroAssembler {
   // are always 0..num_saved_registers_-1)
   int num_saved_registers_;
 
-  // Manage a small pre-allocated pool for writing label targets
-  // to for pushing backtrack addresses.
-  int backtrack_constant_pool_offset_;
-  int backtrack_constant_pool_capacity_;
-
   // Labels used internally.
   Label entry_label_;
   Label start_label_;