servo: Merge #15414 - Use -stdlib=libc++ on mac for stylo bindgen (from upsuper:macos-libcxx); r=emilio

r? @emilio

Source-Repo: https://github.com/servo/servo
Source-Revision: a1d19ca5f831536ee60bb4fa85a9d3ea53c2170e

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 0345f85ba78976b312924e9053c1c15d70bdff4f

servo/components/style/build_gecko.rs

@@ -138,7 +138,12 @@ mod bindings {
             if cfg!(target_os = "linux") {
                 builder = builder.clang_arg("-DOS_LINUX=1");
             } else if cfg!(target_os = "macos") {
-                builder = builder.clang_arg("-DOS_MACOSX=1");
+                builder = builder.clang_arg("-DOS_MACOSX=1")
+                    .clang_arg("-stdlib=libc++")
+                    // To disable the fixup bindgen applies which adds search
+                    // paths from clang command line in order to avoid potential
+                    // conflict with -stdlib=libc++.
+                    .clang_arg("--target=x86_64-apple-darwin");
             } else if cfg!(target_env = "msvc") {
                 builder = builder.clang_arg("-DOS_WIN=1").clang_arg("-DWIN32=1")
                     // For compatibility with MSVC 2015