Make LLVM command-line tools overwrite their output files without -f.

This is conventional command-line tool behavior. -f now just means
"enable binary output on terminals".

Add a -f option to llvm-extract and llvm-link, for consistency.

Remove F_Force from raw_fd_ostream and enable overwriting and
truncating by default. Introduce an F_Excl flag to permit users to
enable a failure when the file already exists. This flag is
currently unused.

Update Makefiles and documentation accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79990 91177308-0d34-0410-b5e6-96231b3b80d8

examples/BrainF/BrainFDriver.cpp

@@ -110,7 +110,6 @@ int main(int argc, char **argv) {
     if (OutputFilename != "-") {
       std::string ErrInfo;
       out = new raw_fd_ostream(OutputFilename.c_str(), ErrInfo,
-                               raw_fd_ostream::F_Force|
                                raw_fd_ostream::F_Binary);
     }
   }