Enable disabling API-based TLS support.

src/IceTLS.h

@@ -52,8 +52,11 @@
 ///
 /// \def ICE_THREAD_LOCAL_HACK
 ///
-#define ICE_THREAD_LOCAL_HACK
-#ifdef ICE_THREAD_LOCAL_HACK
+#ifndef ICE_THREAD_LOCAL_HACK
+#define ICE_THREAD_LOCAL_HACK 1
+#endif
+
+#if ICE_THREAD_LOCAL_HACK
 
 // For a static thread_local field F of a class C, instead of declaring and
 // defining C::F, we create two static fields:

src/IceTypes.cpp

@@ -16,6 +16,8 @@
 
 #include "IceDefs.h"
 
+#include "llvm/Support/ErrorHandling.h"
+
 #include <climits>
 
 namespace Ice {