Can't make a new build during trying to update rtree branch

Hi guys!

Recently I found out, that sql.js has a branch with R-Tree module support. Unfortunately it's quite outdated, so I'm not able to use it with the current Geopackage JS library. According to this issue #59 it needs actually just to add -DSQLITE_ENABLE_RTREE=1 to the make file on master and create a new build.
But when I run make command, I receive this errors:

incorrect target triple 'le32-unknown-nacl' (did you use emcc/em++ on all source files and not clang directly?) LLVM ERROR: Invalid SIMD cast between items of different bit sizes!

I installed emscripten as it described here and here because it looks like the problem described in this FAQ.
But unfortunately it doesn't work.

Could you please help me to solve this issue? Or maybe it would be possible to update rtree branch to the master state, so I can easy include it into a package config? I guess it would be the best solution in my case.

Looking forward to your reply

Start by comparing the rtree branch with master and inspecting the Makefile, then reproduce the reported make failure with the Emscripten setup described in the issue. Verify that the build enables SQLITE_ENABLE_RTREE and produces a current build usable by the Geopackage JS library.