MSVC: add /Brepro to the list of known args (#980)

Co-authored-by: Adrien Guinet <aguinet@quarkslab.com>

src/compiler/msvc.rs

@@ -254,6 +254,7 @@ macro_rules! msvc_args {
 // https://docs.microsoft.com/en-us/cpp/build/reference/compiler-options-listed-alphabetically?view=vs-2019
 msvc_args!(static ARGS: [ArgInfo<ArgData>; _] = [
     msvc_flag!("?", SuppressCompilation),
+    msvc_flag!("Brepro", PassThrough),
     msvc_flag!("C", PassThrough), // Ignored unless a preprocess-only flag is specified.
     msvc_take_arg!("D", OsString, CanBeSeparated, PreprocessorArgument),
     msvc_flag!("E", SuppressCompilation),