tool: Expose family() and deprecate is_like_xxx() wrappers

Intead of adding a new `is_like_xxx()` function every time new
information is needed, or new enumeration variants would be added,
provide the (now `non_exhaustive`) `enum` directly to callers to
match what they're interested in.  Deprecate the existing functions
to point users to the new pattern.

src/lib.rs

@@ -253,8 +253,7 @@ mod command_helpers;
 use command_helpers::*;
 
 mod tool;
-pub use tool::Tool;
-use tool::ToolFamily;
+pub use tool::{Tool, ToolFamily};
 
 mod tempfile;
 
@@ -710,7 +709,7 @@ impl Build {
         let mut cmd = compiler.to_command();
         let is_arm = matches!(target.arch, "aarch64" | "arm");
         let clang = compiler.is_like_clang();
-        let gnu = compiler.family == ToolFamily::Gnu;
+        let gnu = compiler.is_like_gnu();
         command_add_output_file(
             &mut cmd,
             &obj,
@@ -1754,7 +1753,7 @@ impl Build {
         let msvc = target.env == "msvc";
         let compiler = self.try_get_compiler()?;
         let clang = compiler.is_like_clang();
-        let gnu = compiler.family == ToolFamily::Gnu;
+        let gnu = compiler.is_like_gnu();
 
         let is_assembler_msvc = msvc && asm_ext == Some(AsmFileExt::DotAsm);
         let (mut cmd, name) = if is_assembler_msvc {

src/tool.rs

@@ -395,33 +395,44 @@ impl Tool {
         flags
     }
 
+    /// The family of this tool, representing convention of arguments etc.
+    pub fn family(&self) -> ToolFamily {
+        self.family
+    }
+
     /// Whether the tool is GNU Compiler Collection-like.
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub fn is_like_gnu(&self) -> bool {
         self.family == ToolFamily::Gnu
     }
 
     /// Whether the tool is Clang-like.
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub fn is_like_clang(&self) -> bool {
         matches!(self.family, ToolFamily::Clang { .. })
     }
 
     /// Whether the tool is AppleClang under .xctoolchain
     #[cfg(target_vendor = "apple")]
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub(crate) fn is_xctoolchain_clang(&self) -> bool {
         let path = self.path.to_string_lossy();
         path.contains(".xctoolchain/")
     }
     #[cfg(not(target_vendor = "apple"))]
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub(crate) fn is_xctoolchain_clang(&self) -> bool {
         false
     }
 
     /// Whether the tool is MSVC-like.
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub fn is_like_msvc(&self) -> bool {
         matches!(self.family, ToolFamily::Msvc { .. })
     }
 
     /// Whether the tool is `clang-cl`-based MSVC-like.
+    #[deprecated = "Consider matching against the ToolFamily returned by family() instead"]
     pub fn is_like_clang_cl(&self) -> bool {
         matches!(self.family, ToolFamily::Msvc { clang_cl: true })
     }
@@ -441,14 +452,24 @@ impl Tool {
 ///
 /// Detection of a family is done on best-effort basis and may not accurately reflect the tool.
 #[derive(Copy, Clone, Debug, PartialEq)]
+#[non_exhaustive]
 pub enum ToolFamily {
     /// Tool is GNU Compiler Collection-like.
+    #[non_exhaustive]
     Gnu,
     /// Tool is Clang-like. It differs from the GCC in a sense that it accepts superset of flags
     /// and its cross-compilation approach is different.
-    Clang { zig_cc: bool },
-    /// Tool is the MSVC cl.exe.
-    Msvc { clang_cl: bool },
+    #[non_exhaustive]
+    Clang {
+        /// Tool provided by zig
+        zig_cc: bool,
+    },
+    /// Tool is the MSVC `cl.exe`.
+    #[non_exhaustive]
+    Msvc {
+        /// Whether this is `clang-cl` provided by LLVM
+        clang_cl: bool,
+    },
 }
 
 impl ToolFamily {