When emerging dev-vcs/subversion-1.7.13 with USE=-ruby, following warnings are shown during configure: [snip] checking for ruby... (cached) /usr/bin/ruby18 checking rb_hash_foreach... ./configure: line 20777: /usr/bin/ruby18: No such file or directory no configure: WARNING: The detected Ruby is too old for Subversion to use configure: WARNING: A Ruby which has rb_hash_foreach is required to use the configure: WARNING: Subversion Ruby bindings configure: WARNING: Upgrade to the official 1.8.2 release, or later [/snip]
Doesn't look like it's fatal.
This is just a warning, so it does not prevent anyone from building subversion without ruby support. Feel free to report this upstream, so that the ruby check is only done with ruby support enabled.