2009-08-18 Eric Blake <ebb9@byu.net>

2009-08-18  Eric Blake  <ebb9@byu.net>

        * libc/posix/popen.c (popen): Fix documented prototype.

        Improve popen compatibility with glibc.
        * libc/posix/popen.c (popen): The 2006-08-22 change to use
        FD_CLOEXEC disagrees with other implementations; instead, use
        pidlist to work even when fcntl is not available.  Meanwhile,
        support the 'e' modifier to set CLOEXEC, as in glibc.  Drop
        cygwin-specific code, now that cygwin has its own version.
        * libc/posix/Makefile.am (CHEWOUT_FILES): Document popen.
        * libc/posix/posix.tex: New file.