(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