Run your command, then run printenv, capture the output, and set the environment variables from within perl (untested):

/^(\w+)=(.*)/ and $ENV{$1} = $2 for qx(
  . oraenvcommand
  printenv
);
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This breaks on variables with newlines in the value...

Update: Told you it was untested. Fixed code. Still untested. As suggested below, it would be better to run the command before your perl script executes, if at all possible.