[dev-context] texexec patch (recognize pdfxtex in --version)

Hi, Here's a one-line change from me, it makes --version correctly identify the pdfxtex executable. Greetings, Taco [taco@boo web2c]$ diff ~/texmf/scripts/context/perl/texexec.pl /usr/TeX/texmf-dist/scripts/context/perl/texexec.pl 2789c2789 < { /^\s*This is (.*pdf(|e|x)TeX.*?)$/o and $texengine = $1 ; ---

{ /^\s*This is (.*pdf(|e)TeX.*?)$/o and $texengine = $1 ;