In ExecWait(), made the child process exit if it can't execve() the new

program.
Added the use of const (which compiles and is hopefully correct).
Added comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8585 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/SystemUtils.h

@@ -41,5 +41,5 @@ int RunProgramWithTimeout(const std::string &ProgramPath, const char **Args,
 ///  Execute a program with the given arguments and environment and 
 ///  wait for it to terminate.
 ///
-int ExecWait (char ** argv, char ** envp);
+int ExecWait (const char * const argv[], const char * const envp[]);
 #endif