The Opcode module provides functions for the manipulation of sets of
perl opcodes, including the ability to mask (disable) sets of opcodes.

An 'ops' pragma is also provided to allow you to easily disable
opcodes on the command line, e.g.,

	$ perl -Mops=:default ...

	$ perl -M-ops=const -e 1
	constant item trapped by operation mask at -e line 1.

The core of this code originated from version two of the Safe module.
It was split out for simplicity and ease of maintenance. A new version
of the Safe module will use this Opcode module.

This code could be regarded as beta release but the definition of the
optags is not stable and should not be relied upon. Comments welcome.