Create build/llvm dir properly.
Do initial clone without checkout.
Add error exit to build commands.
Make if condition match endif.
Change site url in license headers.
Add mbchk as part of tools build.
With FETCH_ONLY=1 only fetch sources.
Cleanup trailing spaces.
Shorten line lengths.
Mark kernel launcher as NEVER_RETURNS.
Argument to OS_RAISE is an integer.