This avoids inflating the total size of the command line too much. If the input command line is near the max size of a command line (32767 characters), it may grow past that limit when adding the arguments injected by the wrapper. If we excessively quote all arguments that don't need to be quoted, we can more easily run into this situation. Thus, by avoiding excessive quoting, we reduce the risk for this issue to happen. This avoids the issue reported at https://github.com/mstorsjo/llvm-mingw/issues/296.