+#ifdef WINDOWS
+static CRITICAL_SECTION critical_section;
+#define NMEM_ENTER EnterCriticalSection(&critical_section)
+#define NMEM_LEAVE LeaveCriticalSection(&critical_section)
+#else
+#define NMEM_ENTER
+#define NMEM_LEAVE
+#endif
+
+static nmem_block *freelist = NULL; /* "global" freelists */
+static nmem_control *cfreelist = NULL;