linuxdoc-tools-native: Makedoc.sh uses /tmp and fails w/ noexec mount

linuxdoc-tools-native: Makedoc.sh uses /tmp and fails w/ noexec mount

The Makedoc.sh script uses the following line to set TMPDIR

export TMPDIR=`mktemp -d ${TMPDIR:-/tmp}/ldt.XXXXXXXXXX`;

and then later in the script:

chmod u+x $TMPDIR/linuxdoc

Since TMPDIR is not set the script will default to /tmp and if /tmp
is set to noexec (which is becoming more common), the chmod call fails.

Signed-off-by: Konrad Scherer <Konrad.Scherer@windriver.com>
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>