WIP: build.rs: add extra flag

Author: ahayzen-kdab

crates/cxx-qt-lib/build.rs

@@ -270,6 +270,9 @@ fn main() {
     builder.flag_if_supported("/permissive-");
     builder.flag_if_supported("/bigobj");
 
+    // Clang macOS
+    // builder.flag_if_supported("-stdlib=libc++");
+
     // GCC + Clang
     builder.flag_if_supported("-std=c++17");
     // MinGW requires big-obj otherwise debug builds fail