+#include "RtsTypes.h"
+
+#if __GNUC__ >= 3
+/* Assume that a flexible array member at the end of a struct
+ * can be defined thus: T arr[]; */
+#define FLEXIBLE_ARRAY
+#else
+/* Assume that it must be defined thus: T arr[0]; */
+#define FLEXIBLE_ARRAY 0
+#endif
+
+#if defined(SMP) || defined(THREADED_RTS)
+#define RTS_SUPPORTS_THREADS 1
+#endif
+
+/* Fix for mingw stat problem (done here so it's early enough) */
+#ifdef mingw32_TARGET_OS
+#define __MSVCRT__ 1
+#endif
+
+#if defined(__GNUC__)
+#define GNU_ATTRIBUTE(at) __attribute__((at))
+#else
+#define GNU_ATTRIBUTE(at)
+#endif
+
+#if __GNUC__ >= 3
+#define GNUC3_ATTRIBUTE(at) __attribute__((at))
+#else
+#define GNUC3_ATTRIBUTE(at)
+#endif
+
+#define STG_UNUSED GNUC3_ATTRIBUTE(__unused__)
+
+/*
+ * Empty structures isn't supported by all, so to define
+ * empty structures, please protect the defn with an
+ * #if SUPPORTS_EMPTY_STRUCTS. Similarly for use,
+ * employ the macro MAYBE_EMPTY_STRUCT():
+ *
+ * MAYBE_EMPTY_STRUCT(structFoo, fieldName);
+ */
+#if SUPPORTS_EMPTY_STRUCTS
+# define MAYBE_EMPTY_STRUCT(a,b) a b;
+#else
+# define MAYBE_EMPTY_STRUCT(a,b) /* empty */
+#endif
+
+/*
+ * We often want to know the size of something in units of an
+ * StgWord... (rounded up, of course!)
+ */
+#define sizeofW(t) ((sizeof(t)+sizeof(W_)-1)/sizeof(W_))
+
+/*
+ * It's nice to be able to grep for casts
+ */
+#define stgCast(ty,e) ((ty)(e))
+