Update devel/ruby-sexp-processor to 3.0.5.

* Use lang/ruby/gem.mk instead of misc/rubygems/rubygem.mk.
* Remove default value of GEM_BUILD.

=== 3.0.5 / 2010-09-01

* 2 minor enhancements:

  * Added in_context to clean up code.
  * optimize inspect to avoid needlessly caching @line

=== 3.0.4 / 2010-03-27

* 1 minor enhancement:

  * Added line number to pretty_print output if $VERBOSE

(taca)