Many POSIX systems have the bad habit of not restarting interrupted
syscalls. On these systems it's up to the user to check for an error
with errno == EINTR and restart manually. This patch does this for
libgfortran, so that GFortran users don't have to do it.

2016-10-09  Janne Blomqvist  <jb@gcc.gnu.org>

        PR libfortran/67585
        * io/io.h: TEMP_FAILURE_RETRY: Define macro if not found.
        * io/unix.c (raw_read): Handle EINTR.
        (raw_write): Check for return value -1.
        (raw_seek): Handle EINTR.
        (raw_tell): Likewise.
        (raw_size): Likewise.
        (raw_truncate): Likewise.
        (raw_close): Likewise.
        (buf_flush): Call raw_seek instead of lseek.
        (buf_read): Likewise.
        (buf_write): Likewise.
        (fd_to_stream): Handle EINTR.
        (tempfile_open): Likewise.
        (regular_file2): Likewise.
        (compare_file_filename): Likewise.
        (find_file): Likewise.
        (inquire_sequential): Likewise.
        (inquire_direct): Likewise.
        (inquire_formatted): Likewise.

From-SVN: r240902