Use system installed clang for building
Only use system clang on 32bit Linux
Fix building with clang 3.4
Do not contain the Debug build in distribution.

It would saves a lot of time when uploading & downloading on a slow
network, and in the atom branch the debug build is not actually used
too.
Do not export symbols in chromiumviews.

In atom-shell there are too many symbols in chromiumviews that caused
the linker to excceed the symbols number limit when generating the
node.lib.
Add patch for the accelerator.

1. Allow Ctrl+Alt accelerators on Windows.
2. Fix showing text for code key F2 to F22.
Add patch to allow restarting of renderer process on purpose.
Add patch to turn sandbox error message to warm warning.
Add patch to disable renderer hang monitor when page is unloading.

We're doing some GUI work like asking for confirmation in the
beforeunload handler, so it's very likely that the renderer may seem
unresponsive. The default behavior of chromium is to close page, which
is of course not the thing we want.
Add patch to expose necessary members of URLRequestJob.
Add patch to expose "File" class's "path" attribute.
Add patch to fix webview's NSView on Mac.

1. Avoid capturing key event to menu.
https://github.com/atom/atom-shell/issues/170

2. Enable accepting first mouse event.
https://github.com/atom/atom-shell/issues/212
Add patch to make iframe sandboxed by default.

iframes are now sandboxed by default except for following cases:

1. host is localhost.
2. scheme is other than http and file.
3. nested iframes (e.g. iframes in iframe).
Add patch to disable PR_SET_NO_NEW_PRIVS on child process.
Add patch to disable scroll elasticity.