tool: Add is_like_clang_cl() getter

In `ring` we need to check if the compiler is `clang-cl`
to prevent overwriting it with `clang` (see all details in
briansmith/ring#2215), but `cc-rs` does not
currently expose this despite already tracking it.  By adding this
getter we can steer that logic to not overwrite the compiler when it
is `clang-cl`.

Perhaps, since `ToolFamily` is `pub` (but not yet reexported from
`lib.rs`), could we have a public `Tool::family()` getter to not have
to extend these `is_xxx()` getters whenever a downstream crate wants to
know something new?

src/tool.rs

@@ -421,6 +421,11 @@ impl Tool {
         matches!(self.family, ToolFamily::Msvc { .. })
     }
 
+    /// Whether the tool is `clang-cl`-based MSVC-like.
+    pub fn is_like_clang_cl(&self) -> bool {
+        matches!(self.family, ToolFamily::Msvc { clang_cl: true })
+    }
+
     /// Supports using `--` delimiter to separate arguments and path to source files.
     pub(crate) fn supports_path_delimiter(&self) -> bool {
         matches!(