typeprof --version fails on non-CRuby

[eregon]

For example on TruffleRuby:

$ typeprof --version
Currently, TypeProf can work on a Ruby implementation that supports RubyVM::InstructionSequence, such as CRuby.
zsh: exit 1     typeprof --version

If none of typeprof can work on non-CRuby I guess that makes sense, but still shouldn't --version and maybe also --help still work, and only fail when actually needing RubyVM::InstructionSequence?
I think that's what most libraries do and I think it's closer to expected behavior.

Context: I'm updating TruffleRuby to Ruby 3 compatibility.

Another option would be to not include typeprof on TruffleRuby/non-CRuby but I think that's bad because suddenly there would be some expected bundled gem missing, bundle install might fail if typeprof is in it, etc.

[eregon]

If I remove

typeprof/lib/typeprof.rb

Lines 1 to 4 in 02b76ae

	unless defined?(RubyVM::InstructionSequence)
	puts "Currently, TypeProf can work on a Ruby implementation that supports RubyVM::InstructionSequence, such as CRuby."
	exit 1
	end

locally then both --version and --help work.
I think it's much better to fail later here.

[eregon]

RubyVM is only used in 4 places (0.12.0), so I'd suggest to move the check there, just before the actual usages:

$ ack RubyVM lib/gems/gems/typeprof-0.12.0/lib
lib/gems/gems/typeprof-0.12.0/lib/typeprof.rb
1:unless defined?(RubyVM::InstructionSequence)
2:  puts "Currently, TypeProf can work on a Ruby implementation that supports RubyVM::InstructionSequence, such as CRuby."

lib/gems/gems/typeprof-0.12.0/lib/typeprof/iseq.rb
6:      opt = RubyVM::InstructionSequence.compile_option
12:      new(RubyVM::InstructionSequence.compile_file(file, **opt).to_a)
16:      opt = RubyVM::InstructionSequence.compile_option
22:      new(RubyVM::InstructionSequence.compile(str, path, **opt).to_a)

[mame]

Thanks! It looks reasonable. I'll do later