Make sys::Program::ExecuteAndWait not throw exceptions and update any affected code. It now return -9999 to signal that the program couldn't be executed. Only one case (in bugpoint) actually examines the result code. llvm-svn: 29785
llvm-svn: 28939
-x none, to not foul up autodetection of .a file or .dylibs. llvm-svn: 28741
llvm-svn: 28699