Add -isysroot for xctoolchain cc

Author: youknowone

src/lib.rs

@@ -2111,7 +2111,7 @@ impl Build {
             None => false,
         };
 
-        let is_sim = match target.split('-').nth(3) {
+        let is_arm_sim = match target.split('-').nth(3) {
             Some(v) => v == "sim",
             None => false,
         };
@@ -2139,14 +2139,14 @@ impl Build {
                     ));
                 }
             }
-        } else if is_sim {
+        } else if is_arm_sim {
             match arch {
                 "arm64" | "aarch64" => ArchSpec::Simulator("-arch arm64"),
                 "x86_64" => ArchSpec::Simulator("-m64"),
                 _ => {
                     return Err(Error::new(
                         ErrorKind::ArchitectureInvalid,
-                        "Unknown architecture for iOS simulator target.",
+                        "Unknown architecture for simulator target.",
                     ));
                 }
             }
@@ -2210,11 +2210,15 @@ impl Build {
             ArchSpec::Catalyst(_) => "macosx".to_owned(),
         };
 
-        if !is_mac {
+        // AppleClang sometimes needs sysroot even for darwin
+        if cmd.is_xctoolchain_clang() || !target.ends_with("-darwin") {
             self.print(&format!("Detecting {} SDK path for {}", os, sdk));
             let sdk_path = self.apple_sdk_root(sdk.as_str())?;
             cmd.args.push("-isysroot".into());
             cmd.args.push(sdk_path);
+        }
+
+        if !is_mac {
             cmd.args.push("-fembed-bitcode".into());
         }
         /*
@@ -3112,6 +3116,17 @@ impl Tool {
         self.family == ToolFamily::Clang
     }
 
+    /// Whether the tool is AppleClang under .xctoolchain
+    #[cfg(target_vendor = "apple")]
+    fn is_xctoolchain_clang(&self) -> bool {
+        let path = self.path.to_str().unwrap();
+        path.contains(".xctoolchain/")
+    }
+    #[cfg(not(target_vendor = "apple"))]
+    fn is_xctoolchain_clang(&self) -> bool {
+        false
+    }
+
     /// Whether the tool is MSVC-like.
     pub fn is_like_msvc(&self) -> bool {
         match self.family {

tests/test.rs

@@ -439,6 +439,8 @@ fn gnu_apple_darwin() {
             .file("foo.c")
             .compile("foo");
 
-        test.cmd(0).must_have("-mmacosx-version-min=10.4");
+        let cmd = test.cmd(0);
+        cmd.must_have("-mmacosx-version-min=10.4");
+        cmd.must_not_have("-isysroot");
     }
 }