For PR797:
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
diff --git a/llvm/tools/lto/lto.cpp b/llvm/tools/lto/lto.cpp
index 162bac9..570558a 100644
--- a/llvm/tools/lto/lto.cpp
+++ b/llvm/tools/lto/lto.cpp
@@ -334,7 +334,7 @@
   args.push_back(tmpAsmFilePath.c_str());
   args.push_back(0);
 
-  int R1 = sys::Program::ExecuteAndWait(gcc, &args[0], 0, 0, 1);
+  sys::Program::ExecuteAndWait(gcc, &args[0], 0, 0, 1);
 
   tmpAsmFilePath.eraseFromDisk();