* include/unistd.h (ftruncate): Add inline definition.

* mingwex/ftruncate.c: New file.
	* mingwex/Makefile.in: Add ftruncate.o to libmingwex.a.

winsup/mingw/include/unistd.h

@@ -14,4 +14,20 @@
 #include <getopt.h>
 #undef __UNISTD_GETOPT__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This is defined as a real library function to allow autoconf
+   to verify its existence. */
+int ftruncate(int, off_t);
+__CRT_INLINE int ftruncate(int __fd, off_t __length)
+{
+  return _chsize (__fd, __length);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _UNISTD_H */