Use --gnu in parralell and XX for mktemp

Signed-off-by: Mansour Behabadi <mansour@oxplot.com>
Make src scripts executable

Signed-off-by: Mansour Behabadi <mansour@oxplot.com>
merged pull request from oxplot
tmpfiles to $TMPDIR + better portability (mktemp)

mktemp: consider both FreeBSD/OSX and Linux OS having incompatible
syntax
From now on temporary files are saved in the folder specified by the
environment variable $TMPDIR