fix: envsubst when variable contains a '&'

  }

  function awkenvsubst() {

    awk '{while(match($0,"[$%]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);val=ENVIRON[var]; gsub("[$%]{"var"}",val)}}1'

    # escapes '&' char in variables for gsub

    awk '!/# *nosubst/{while(match($0,"[$%]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);val=ENVIRON[var];gsub("&","\\\\&",val);gsub("[$%]{"var"}",val)}}1'

  }

  function pre_apply() {