kripken/emscripten — pull request #2091 by sunfishcode (2014-02-04 00:03:34+00:00)
Title:  Use -mllvm -disable-llvm-optzns.

The -O options affect the clang front-end in a variety of ways, so allow
them to be passed through to clang. To disable just the optimization passes,
use -mllvm -disable-llvm-optzns.