getopts.pl was removed in Perl v5.16. Although you could install Perl4::CoreLibs to get it back, I'd strongly recommend you switch to the core module Getopt::Std or Getopt::Long - often the replacement is pretty simple; in particular, have a look at getopts from Getopt::Std.

getopts.pl says:

This library is no longer being maintained, and is included for backward compatibility with Perl 4 programs which may require it.

In particular, this should not be used as an example of modern Perl programming techniques.

Suggested alternatives: Getopt::Long or Getopt::Std