SpiderMonkey upgrade details

Latest revision: 5ecd532a167e

Grab latest SpiderMonkey source:

cd ~/mozilla-central
make -C objdir/js/src source-package
cd ~/servo/src/support/mozjs
rm -rf .
cp ~/mozilla-central/objdir/mozjs-31.0.1.tar.bz2 .
tar xvjf mozjs-31.0.1.tar.bz2 --strip 1

Port non-upstreamed patches forward:

• https://github.com/mozilla-servo/mozjs/commit/307dd4bd397100a5446fb3d8d5868fc052577d3a
• https://github.com/mozilla-servo/mozjs/commit/bfe6b9544ff0df852bdca16a68770b9381e5f35c
• https://github.com/mozilla-servo/mozjs/commit/81aeed0b6159acdedf7dd530fb6c3bde5ddbb70a
• https://github.com/mozilla-servo/mozjs/commit/2f49752829e5cf68b68caee62c338a7c989c7992

Upgrade bindgen:

• Check out external copy of LLVM, follow clang instructions
• Update to last official revision used by Servo's Rust's copy
• Check out revisions of compiler-rt and clang that are from approximately the same date as official revision
• configure --enable-optimized; make
• Add a symlink to the newly built libclang.so and libclang.a sitting in rust-bindgen's working dir
• Find a revision of bindgen that builds with Servo's current rustc
• Build bindgen with Servo's rustc.

./bindgen -allow-bitfields -l mozjs -o jsapi.rs -match js -x c++ -std=c++11 -D __STDC_LIMIT_MACROS -D SERVO_NO_OVERLOAD ~/sdb/servo/src/support/spidermonkey/mozjs/js/src/jsapi.h -I ~/sdb/servo/build/x86_64-unknown-linux-gnu/src/support/spidermonkey/mozjs/dist/include/ -isystem /usr/lib/x86_64-linux-gnu/gcc/x86_64-linux-gnu/4.5/include -isystem /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include -isystem /usr/local/include/c++/4.6.3/ -isystem /usr/local/include/c++/4.6.3/x86_64-unknown-linux-gnu/