[ruby-core:24167] thought for RbConfig::CONFIG['ruby_version']

Currently for both 1.8.6 and 1.8.7, RbConfig::CONFIG['ruby_version']
== '1.8' # meaning that they are both designated as binary compatible
for gem installs.

Unfortunately that is not always the case [ex: rev, rmagick, etc.]

Thus if you install both 1.8.6 and 1.8.7 on the same machine the
binaries of gems compiled by both might accidentally override each
other, which is not expected.

Ruby 1.9, however, has RbConfig::CONFIG['ruby_version'] == '1.9.1'

Fix: possibly for the 1.8.8 branch set it to '1.8.8' unless it is
strictly binary compatible?

Thoughts?

=r