The most significant 32 bits of a 64 bit long return value get passed in the global tempRet0, but this fails when asm.js and/or closure are enabled as tempRet0 was declared again inside the asm closure. This fix exports tempRet0 via an accessor method Runtime.getTempRet0() which is visible with or without optimisations being enabled
Committing the actual change now
Fixed finger trouble typo added to emscripten.py
In fastcomp  we actually need only tempRet0 and no higher indexes, removed the higher indexes
Removed redundant wrapping function around Runtime.stackAlloc, Runtime.stackSave and Runtime.stackRestore assignments to their respective versions in the asm namespace. Reran test suite and retested with my own app which makes heavy use of stackSave and stackRestore.
add Runtime.setTempRet0 method for symmetry
Merge pull request #2311 from fadams/fix-64bit-long-return-issue

Fix 64bit long return issue