qt-build-utils: use cc::Build insteaed of Option<cc::Build>

Whether to link the .o files is now controlled by a Cargo option,
not the calling code.

Author: Be-ing

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

@@ -400,7 +400,7 @@ impl CxxQtBuilder {
 
         let mut qtbuild = qt_build_utils::QtBuild::new(self.qt_modules.into_iter().collect())
             .expect("Could not find Qt installation");
-        qtbuild.cargo_link_libraries(Some(&mut self.cc_builder));
+        qtbuild.cargo_link_libraries(&mut self.cc_builder);
 
         // Write cxx-qt-lib and cxx headers
         cxx_qt_lib_headers::write_headers(format!("{header_root}/cxx-qt-lib"));

crates/cxx-qt-lib/Cargo.toml

@@ -39,3 +39,4 @@ qt_gui = ["cxx-qt-lib-headers/qt_gui"]
 qt_qml = ["cxx-qt-lib-headers/qt_qml"]
 time = ["dep:time"]
 url = ["dep:url"]
+link_qt_object_files = ["qt-build-utils/link_qt_object_files"]

crates/cxx-qt-lib/build.rs

@@ -16,7 +16,7 @@ fn main() {
     }
 
     let qtbuild = qt_build_utils::QtBuild::new(qt_modules).expect("Could not find Qt installation");
-    qtbuild.cargo_link_libraries(None);
+
     // Required for tests
     qt_build_utils::setup_linker();
 
@@ -182,6 +182,8 @@ fn main() {
     let mut builder =
         cxx_build::bridges(rust_bridges.iter().map(|bridge| format!("src/{bridge}.rs")));
 
+    qtbuild.cargo_link_libraries(&mut builder);
+
     let mut cpp_files = vec![
         "core/qbytearray",
         "core/qcoreapplication",

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

@@ -313,7 +313,7 @@ impl QtBuild {
         lib_path: &str,
         link_lib: &str,
         prl_path: &str,
-        builder: &mut Option<&mut cc::Build>,
+        builder: &mut cc::Build,
     ) {
         println!("cargo:rustc-link-lib={link_lib}");
 
@@ -376,7 +376,7 @@ impl QtBuild {
     }
 
     /// Tell Cargo to link each Qt module.
-    pub fn cargo_link_libraries(&self, mut builder: Option<&mut cc::Build>) {
+    pub fn cargo_link_libraries(&self, builder: &mut cc::Build) {
         let prefix_path = self.qmake_query("QT_INSTALL_PREFIX");
         let lib_path = self.qmake_query("QT_INSTALL_LIBS");
         println!("cargo:rustc-link-search={lib_path}");
@@ -423,7 +423,7 @@ impl QtBuild {
                 &lib_path,
                 &link_lib,
                 &prl_path,
-                &mut builder,
+                builder,
             );
         }
 
@@ -440,7 +440,7 @@ impl QtBuild {
                 &lib_path,
                 "qwasm",
                 &format!("{platforms_path}/libqwasm.prl"),
-                &mut builder,
+                builder,
             );
         }
     }

crates/qt-build-utils/src/parse_cflags.rs

@@ -109,11 +109,7 @@ fn split_flags(link_args: &[u8]) -> Vec<String> {
     words
 }
 
-pub(crate) fn parse_libs_cflags(
-    name: &str,
-    link_args: &[u8],
-    _builder: &mut Option<&mut cc::Build>,
-) {
+pub(crate) fn parse_libs_cflags(name: &str, link_args: &[u8], _builder: &mut cc::Build) {
     let mut is_msvc = false;
     let target = env::var("TARGET");
     if let Ok(target) = &target {
@@ -178,7 +174,7 @@ pub(crate) fn parse_libs_cflags(
                         let file_name = file_name.to_string_lossy();
                         if file_name.ends_with(".o") {
                             #[cfg(feature = "link_qt_object_files")]
-                            if let Some(builder) = _builder {
+                            {
                                 let path_string = path.to_string_lossy().to_string();
                                 unsafe {
                                     // Linking will fail with duplicate symbol errors if the same .o file is linked twice.
@@ -192,7 +188,7 @@ pub(crate) fn parse_libs_cflags(
                                         // https://github.com/rust-lang/rust/issues/99427#issuecomment-1562092085
                                         // TODO: remove builder argument when it's not used anymore to link object files.
                                         // also remove the dependency on cc when this is done
-                                        builder.object(path);
+                                        _builder.object(path);
                                     }
                                     LINKED_OBJECT_FILES.get_mut().unwrap().insert(path_string);
                                 }