Merge trunk revision: 39366
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39392 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Merge trunk revision: 39366
install destination before building extension. Patch by Kenta Murata.
[ruby-trunk - Bug #7897]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@39392 b2dd03c8-39d4-4d8f-98ff-823fe69b080e