win/clang: Remove unused variables in 32-bit builds.

sandbox/win/src/process_mitigations.cc

Index: sandbox/win/src/process_mitigations.cc
diff --git a/sandbox/win/src/process_mitigations.cc b/sandbox/win/src/process_mitigations.cc
index 8963fc882fb6d43f1a8bc8fdc0cf62fb1ab175ab..f1bc090c0affe9b09d0c2dc8d186111e75b7ad74 100644
--- a/sandbox/win/src/process_mitigations.cc
+++ b/sandbox/win/src/process_mitigations.cc
@@ -87,7 +87,6 @@ bool ApplyProcessMitigationsToCurrentProcess(MitigationFlags flags) {
     } else {
       // We're on XP sp2, so use the less standard approach.
       // For reference: http://www.uninformed.org/?v=2&a=4
-      static const int MEM_EXECUTE_OPTION_ENABLE = 1;
       static const int MEM_EXECUTE_OPTION_DISABLE = 2;
       static const int MEM_EXECUTE_OPTION_ATL7_THUNK_EMULATION = 4;
       static const int MEM_EXECUTE_OPTION_PERMANENT = 8;