\DeclareFontFamily{T1}{cmssq}{}
\DeclareFontShape{T1}{cmssq}{m}{n}{
  <8> <8.76> <9.6> <11.52> <13.82> <16.59> <19.91> ecsq8
}{}
\DeclareFontShape{T1}{cmssq}{m}{sl}{
  <8> <8.76> <9.6> <11.52> <13.82> <16.59> <19.91> ecqi8
}{}
\DeclareFontShape{T1}{cmssq}{m}{it}{
  <-> ssub * cmssq/m/sl
}{}
\endinput