Update devel/ruby-debug-base to 0.10.3.

* Use lang/ruby/gem.mk instead of misc/rubygems/rubygem.mk.
* Update HOMEPAGE.
* Add LICENSE.

0.10.3
11/17/08

- a backtrace now warns when it thinks the callstack is truncated which it
  gets by comparing with caller()
- fix setting $0.
- fix bug in showing variables in post-mortem
- Document how Debugger.start with a block is intended to be used.
- Move Kernel#debugger from ruby-debug-base into ruby-debug
- Get regression tests working again
- Warn and add a "confirmation" when setting a breakpoint on a
  file that is not loaded.

(taca)