* Implemented flock() semantics to the advisory locking backend. Not tested

(must also compare to BSD; I've looked at their sources, but I might have
  missed something).
* Added sys/file.h and the flock() system call.
* common_fcntl() could forget to put back the file descriptor on some error
  conditions (I guess we should introduce and use a DescriptorGetter class).
* Cleaned up fcntl.h, moved the BSD extensions S_IREAD and S_IWRITE to
  sys/stat.h where they belong, and added the missing S_IEXEC to them.
* Added some more comments.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23836 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/posix/fcntl.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2007, Haiku Inc. All Rights Reserved.
+ * Copyright 2002-2008, Haiku Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _FCNTL_H
@@ -74,15 +74,6 @@ struct flock {
 	pid_t	l_pid;
 };
 
-/* for use with flock() - TODO: this should be moved to sys/file.h *if* we'll support flock() one day */
-#define	LOCK_SH		0x01	/* shared file lock */
-#define	LOCK_EX		0x02	/* exclusive file lock */
-#define	LOCK_NB		0x04	/* don't block when locking */
-#define	LOCK_UN		0x08	/* unlock file */
-
-#define S_IREAD		0x0100  /* owner may read */
-#define S_IWRITE	0x0080	/* owner may write */
-
 
 #ifdef __cplusplus
 extern "C" {
@@ -99,4 +90,4 @@ extern int	fcntl(int fd, int op, ...);
 }
 #endif
 
-#endif /* _FCNTL_H */
+#endif	/* _FCNTL_H */