# parse variable assignments out of the file
while ($ebuildcontents =~ /\b([-A-Z0-9_]+)=\"(.*?)\"{1}?/sgc) {
  $ebuildvars{$1} = $2;
}

##</code><code>##

foreach (keys %ebuildvars) {
  $ebuildvars{$_} =~ s/\$\{?([-A-Z0-9_]+)\}?/$ebuildvars{$1}/gs;
}