break

crates/cxx-qt-build/src/lib.rs

@@ -537,7 +537,6 @@ impl CxxQtBuilder {
             builder.flag_if_supported("-Wa,-mbig-obj");
             // macOS
             builder.flag_if_supported(&format!("-mmacosx-version-min={}", macos_deployment_target));
-            builder.file(&format!("{}/broken.cpp", env!("CARGO_MANIFEST_DIR")));
             // Enable Qt Gui in C++ if the feature is enabled
             #[cfg(feature = "qt_gui")]
             builder.define("CXX_QT_GUI_FEATURE", None);

crates/cxx-qt-lib/Cargo.toml

@@ -29,6 +29,7 @@ url = { version = "2.3", optional = true }
 cxx-build.workspace = true
 cxx-qt-lib-headers.workspace = true
 qt-build-utils.workspace = true
+versions.workspace = true
 
 [features]
 default = ["qt_gui", "qt_qml"]

crates/cxx-qt-lib/build.rs

@@ -3,6 +3,9 @@
 //
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
+use std::env;
+use versions::SemVer;
+
 fn main() {
     let feature_qt_gui_enabled = std::env::var("CARGO_FEATURE_QT_GUI").is_ok();
     let feature_qt_qml_enabled = std::env::var("CARGO_FEATURE_QT_QML").is_ok();
@@ -280,6 +283,30 @@ fn main() {
         builder.define("CXX_QT_QML_FEATURE", None);
     }
 
+    // With macOS we need
+    //   - std::filesystem::path from 10.15
+    //   - std::shared_mutex from 10.12
+    static MACOS_DEPLOYMENT_TARGET_MINIMUM: &str = "10.15";
+    let macos_deployment_target = match env::var("MACOSX_DEPLOYMENT_TARGET") {
+        Ok(v) => {
+            let version = if v.is_empty() {
+                SemVer::new(MACOS_DEPLOYMENT_TARGET_MINIMUM).unwrap()
+            } else {
+                SemVer::new(&v).expect(
+                    "MACOSX_DEPLOYMENT_TARGET environment variable set but could not parse it as a version.",
+                )
+            };
+
+            if version < SemVer::new(MACOS_DEPLOYMENT_TARGET_MINIMUM).unwrap() {
+                println!("cargo:warning=CXX-Qt requires MACOSX_DEPLOYMENT_TARGET >= 10.15, using 10.15.");
+                MACOS_DEPLOYMENT_TARGET_MINIMUM.to_owned()
+            } else {
+                v
+            }
+        }
+        Err(_) => MACOS_DEPLOYMENT_TARGET_MINIMUM.to_owned(),
+    };
+
     // Note, ensure our settings stay in sync across cxx-qt-build and cxx-qt-lib
     builder.cpp(true);
     // MSVC
@@ -289,6 +316,9 @@ fn main() {
     builder.flag_if_supported("/bigobj");
     // GCC + Clang
     builder.flag_if_supported("-std=c++17");
+    // macOS
+    builder.flag_if_supported(&format!("-mmacosx-version-min={}", macos_deployment_target));
+    builder.file(&format!("{}/src/broken.cpp", env!("CARGO_MANIFEST_DIR")));
     // MinGW requires big-obj otherwise debug builds fail
     builder.flag_if_supported("-Wa,-mbig-obj");