Upgrade SpiderMonkey again

[Philip]

Should upgrade it some time, to get bug fixes and performance improvements etc.

Some notes that I don't want to forget:

• Use JS_NewCompartmentAndGlobalObject for the first context per runtime (to make them all share a compartment).
• JS_THREADSAFE (and NSPR) is obligatory.
• ​Setter change.
• ​JS_GetStringChars is dead.

[Philip]

This mostly works with 9aac1cc64794, except for profiling of functions registered by InterfaceScripted.h. Also the warning disabling is ugly, and I haven't tested on Windows, and this probably won't work with JS_THREADSAFE yet.

Performance improvements seem negligible so I don't care enough to finish this off yet.

[Philip]

To test:

• Apply the patch (probably patch -p1 < sm-upgrade2.diff or something).
• Create libraries/spidermonkey/
• Save build.sh in there.
• Save ​js185 in there (don't extract it manually).
• Run build.sh from its directory; that should successfully build SpiderMonkey.
• Do a clean rebuild of the game.

The problem I get is that all the script-created widgets in Atlas are stuck at position (0,0), like their sizers aren't automatically running their layout code, and I have no idea why.

[philip]

(In [9852]) Upgrade to SpiderMonkey? 1.8.5 (fixes #734)