On non-windows, when preprocessing with clang-cl, -xc needs to be -Xc…

…lang -xc

Closes: #68

src/non_windows.rs

@@ -88,8 +88,7 @@ impl Compiler {
             CompilerType::LlvmRc { has_no_preprocess } => {
                 let preprocessed_path = format!("{}/{}-preprocessed.rc", out_dir, prefix);
                 fs::write(&preprocessed_path,
-                          apply_macros_cc(cc::Build::new().define("RC_INVOKED", None), macros)
-                              .flag("-xc")
+                          cc_xc(apply_macros_cc(cc::Build::new().define("RC_INVOKED", None), macros))
                               .file(resource)
                               .cargo_metadata(false)
                               .include(out_dir)
@@ -137,6 +136,14 @@ fn apply_macros_cc<'t, Ms: AsRef<OsStr>, Mi: IntoIterator<Item = Ms>>(to: &'t mu
     to
 }
 
+fn cc_xc(to: &mut cc::Build) -> &mut cc::Build {
+    if to.get_compiler().is_like_msvc() {  // clang-cl
+        to.flag("-Xclang");
+    }
+    to.flag("-xc");
+    to
+}
+
 fn try_command(cmd: &mut Command, exec: &Path, action: &str, whom: &str, whre: &str) {
     match cmd.status() {
         Ok(stat) if stat.success() => {}