4.6.7.6 MF: Specify Dependency File Option
The -MF file option specifies a file in which to
write the dependencies for the -M or -MM options. If no
-MF option is given, the preprocessor sends the rules to the same place
it would have sent preprocessed output.
When used with the driver options, -MD or
-MMD, -MF, overrides the default dependency output
file.
