diff --git a/include/loki/Threads.h b/include/loki/Threads.h
index af158ca..97ef97b 100644
--- a/include/loki/Threads.h
+++ b/include/loki/Threads.h
@@ -62,7 +62,7 @@ namespace Loki
         { lval = val; }
     };
     
-#ifdef _WINDOWS_
+#if defined(_WINDOWS_) && defined(_WINDOWS_H) // && defined(__WIN32)
 
 ////////////////////////////////////////////////////////////////////////////////
 // class template ObjectLevelLockable
@@ -81,7 +81,7 @@ namespace Loki
             ::InitializeCriticalSection(&mtx_);
         }
         
-        ObjectLevelLockable( const ObjectLevelLockable& )
+        ObjectLevelLockable(const ObjectLevelLockable&)
         {
             ::InitializeCriticalSection(&mtx_);
         }
diff --git a/tools/RegressionTest/SingletonTest.h b/tools/RegressionTest/SingletonTest.h
index 49d2786..8d368e8 100644
--- a/tools/RegressionTest/SingletonTest.h
+++ b/tools/RegressionTest/SingletonTest.h
@@ -77,7 +77,7 @@ namespace
   typedef SingletonHolder<MyClass<20>, CreateStatic, NoDestroy, SingleThreaded> t20;
 
 //#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) && !defined(__MWERKS__)
-#ifdef _WINDOWS_
+#if defined(_WINDOWS_) && defined(_WINDOWS_H) // && defined(__WIN32)
 
   typedef SingletonHolder<MyClass<5>, CreateUsingNew, DefaultLifetime, ClassLevelLockable> t5;
   typedef SingletonHolder<MyClass<6>, CreateUsingNew, PhoenixSingleton, ClassLevelLockable> t6;
@@ -128,7 +128,7 @@ public:
     MAKE_TEST(t20)
 
 //#if defined(_MSC_VER) && !defined(__INTEL_COMPILER) && !defined(__MWERKS__)
-#ifdef _WINDOWS_
+#if defined(_WINDOWS_) && defined(_WINDOWS_H) // && defined(__WIN32)
 
     MAKE_TEST(t5)
     MAKE_TEST(t6)
diff --git a/tools/RegressionTest/Test.cpp b/tools/RegressionTest/Test.cpp
index e142ac8..da82d25 100644
--- a/tools/RegressionTest/Test.cpp
+++ b/tools/RegressionTest/Test.cpp
@@ -18,7 +18,7 @@
 # pragma warning(disable: 4018 4097 4100 4213 4290 4512 4514 4700 4702 4710 4786 4800)
 #endif
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) || defined(__MINGW32__)
 #include <Windows.h> // for threads, part of the sdk, disable if not found
 #endif