\ifxetex
% to have the \text macro
\usepackage{amstext}
% to have the align environment
\usepackage{amsmath}

\def\sf@sfdefault{sf}
\def\sf@rmdefault{rm}
\def\sf@ttdefault{tt}

\def\savefont{%
  %\bgroup%
  \expandafter\edef\expandafter\sf@series\expandafter{\f@series}%
  \expandafter\edef\expandafter\sf@shape\expandafter{\f@shape}%
  %\sf@series
  \ifx\f@family\sfdefault
    \let\sf@family\sf@sfdefault
  \else\ifx\f@family\rmdefault
    \let\sf@family\sf@rmdefault
  \else\ifx\f@family\ttdefault
    \let\sf@family\sf@ttdefault
  \else
    \ifthenelse{\equal{\f@family}{\ttdefault}}{
      \let\sf@family\sf@ttdefault }{ \let\sf@family\relax }
  \fi\fi\fi%
  %\egroup%
}
\def\restorefont{%
  %\bgroup%
  \def\f@series{\sf@series}%
  \def\f@shape{\sf@shape}%
  \ifx\sf@family\sf@sfdefault
    \sffamily
  \else\ifx\sf@family\sf@rmdefault
    \rmfamily
  \else\ifx\sf@family\sf@ttdefault
    \ttfamily
  \fi\fi\fi%
  \selectfont%
  %\egroup%
}

\def\savefamily{%
  \ifx\f@family\sfdefault
    \let\sf@family\sf@sfdefault
  \else\ifx\f@family\rmdefault
    \let\sf@family\sf@rmdefault
  \else\ifx\f@family\ttdefault
    \let\sf@family\sf@ttdefault
  \else
    \ifthenelse{\equal{\f@family}{\ttdefault}}{
      \let\sf@family\sf@ttdefault}{\let\sf@family\relax}
  \fi\fi\fi%
}
\def\loadfamily{%
  \ifx\sf@family\sf@sfdefault
    \sffamily
  \else\ifx\sf@family\sf@rmdefault
    \rmfamily
  \else\ifx\sf@family\sf@ttdefault
    \ttfamily
  \else
    \rmfamily
  \fi\fi\fi%
  \selectfont%
}

% Copy the fontspec macro, but don't switch to normal font
\newcommand*\switchmainfont[2][]{%
  \zf@fontspec{#1}{#2}%
  \let\rmdefault\zf@family
  \selectfont}
\newcommand*\switchsansfont[2][]{%
  \zf@fontspec{#1}{#2}%
  \let\sfdefault\zf@family
  \selectfont}
\newcommand*\switchmonofont[2][]{%
  \zf@fontspec{#1}{#2}%
  \let\ttdefault\zf@family
  \selectfont}

\else

% Math Support
\usepackage{mathrsfs}
\usepackage{amsmath}
\usepackage{amssymb}

% Use PostScript fonts
%
% Since mathptmx is included the following symbols are saved to prevent
% from a clash, even if the symbols actually appear as black boxes...
%
\let\stdcoprod=\coprod
\let\stdamalg=\amalg
\let\stdjmath=\jmath
\usepackage{mathptmx}
\let\coprod=\stdcoprod
\let\amalg=\stdamalg
\let\jmath=\stdjmath
\usepackage[scaled=.90]{helvet}
\usepackage{courier}

% More characters
\usepackage{pifont}
\usepackage{textcomp}

\fi