patch for touch.c allowing O_EXCL

[Andreas Aardal Hanssen]

Hi!

This patch allows the command line option '-x', which enables
create-if-exist.

On file opening, if the file already exists, touch will exit with
errorcode 1 without changing the state of the target file. If the file
doesn't exist, it is created and the return code of touch is 0. This
is an atomic operation allowing touch to do TAS (test-and-set).

This allows creation of critical regions in bash scripts.

if touch -x .lock; then
    # critical region begin

    # critical region end
    rm -f .lock
fi

Best regards,

Andreas

fileutils-4.1-touch-mutex-patch
Description: fileutils-4.1-touch-mutex-patch