LaTeX: To utilize PGF's position marking on e-pTeX

pxpgfmark.sty

% pxpgfmark.sty
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{pxpgfmark}[2013/02/18 v0.1]
\@ifpackageloaded{pgfcore}{}{%else
  \PackageError{pxpgfmark}{Package 'pgfcore' must be loaded}\@ehc}
\def\pxqmk@tempa{pgfsys-dvipdfmx.def}
\ifx\pgfsysdriver\pxqmk@tempa
  \@tempswatrue
  \ifx\pdfsavepos\@undefined \@tempswafalse \fi
  \ifx\pdflastxpos\@undefined \@tempswafalse \fi
  \ifx\pdflastypos\@undefined \@tempswafalse \fi
  \ifx\pgf@sys@pdf@dvi@tracker\@undefined \@tempswafalse \fi
  \if@tempswa
    \pgf@sys@pdf@dvi@tracker
    \PackageInfo{pxpgfmark}{Position marking enabled}
  \fi
\fi
%% EOF