improve debug logging of emcc invocation
remove stack parameter from js optimizer traverse(), to avoid overhead when not needed
fix test_files_m on latest spidermonkey, which shows more warnings
add fuzz testcase for nested i24 constantExprs
fix SDL bug where freeing the surface screen did not work properly
add fastcomp env var to library builds in test runner, to fix errors in slow2asm.test_the_bullet
Merge remote-tracking branch 'upstream/incoming' into incoming