// be released, partial pages will not.)
extern void TCMalloc_SystemRelease(void* start, size_t length);
+extern void TCMalloc_SystemCommit(void* start, size_t length);
+
+#if !HAVE(MADV_FREE_REUSE) && !HAVE(MADV_DONTNEED) && !HAVE(MMAP) && !HAVE(VIRTUALALLOC)
+inline void TCMalloc_SystemRelease(void*, size_t) { }
+#endif
+
+#if !HAVE(VIRTUALALLOC) && !HAVE(MADV_FREE_REUSE)
+inline void TCMalloc_SystemCommit(void*, size_t) { }
+#endif
+
#endif /* TCMALLOC_SYSTEM_ALLOC_H__ */