install libspatialindex on macOS

ref: https://github.com/libspatialindex/libspatialindex/wiki/1.-Getting-Started

1. install homeberw
2. brew install curl
3. brew install make
4. brew install gcc

5. curl -L http://download.osgeo.org/libspatialindex/spatialindex-src-1.8.5.tar.gz | tar xz
   cd spatialindex-src-1.8.5
   ./configure
   make
   sudo make install
   sudo update_dyld_shared_cache