Redirect _Unwind_RaiseException to __pnacl_eh_sjlj_Unwind_RaiseException for PNaCl targets.
Don't try to set sigpipe to ignore on NaCl.
Merge branch 'master' of https://github.com/mozilla/rust into try-merge

Conflicts:
	src/liblibc/lib.rs
	src/libsyntax/abi.rs