mxcl/homebrew — pull request #8584 by springmeyer (2011-11-14 21:08:23+00:00)
Title: -O3/-O2 leads to corrupt rtree indexes on 10.6/10.7 with both gcc and ll...

## tl;dr:

Sqlite's rtree extension does not work properly when built with high levels of compiler optimization. Even sqlite trunk suffers from this, so a workaround is needed at build time. This issue is rarely seen (outside of homebrew installs) because SQLite amalgamation defaults to not setting the -ON flag itself and the apple provided sqlite uses `-Os` (and does nto suffer from this bug in rtree). Please accept this change so that rtree indexes work with homebrew provided sqlite.

More background: https://github.com/mapbox/tilemill/issues/712.