* tool/rbuninstall.rb: remove symlinks.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39635 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: suppress error messages

* configure.in: suppress error messages, rm: cannot remove
  'conftest.dSYM', from AC_EGREP_CPP with CFLAGS=-g on Darwin.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39636 b2dd03c8-39d4-4d8f-98ff-823fe69b080e