/proc/self is not portable

[Christopher O Cowan]

I'm compiling on AIX, and while it does have a /proc fs, it does not have
the self symlink.   Should this be refactored to do the explicit getpid()
instead?

I found 3 instances of this:

$ git grep -n  '/proc/self'
lib/replace/closefrom.c:56:     dirp = opendir("/proc/self/fd");
source4/ntvfs/cifs_posix_cli/svfs_util.c:169:   ret = asprintf(&fd_path,
"/proc/self/%d", fd);
source4/ntvfs/simple/svfs_util.c:162:   ret = asprintf(&fd_path,
"/proc/self/%d", fd);

Regards,
Chris