swift: Pass C base compile options to swiftc

mesonbuild/compilers/swift.py

@@ -13,6 +13,7 @@
 
 
 if T.TYPE_CHECKING:
+    from .. import build
     from ..dependencies import Dependency
     from ..envconfig import MachineInfo
     from ..environment import Environment
@@ -115,6 +116,21 @@ def get_include_args(self, path: str, is_system: bool) -> T.List[str]:
     def get_compile_only_args(self) -> T.List[str]:
         return ['-c']
 
+    def get_option_compile_args(self, target: build.BuildTarget, env: Environment, subproject: T.Optional[str] = None
+                                ) -> T.List[str]:
+        args: T.List[str] = []
+
+        # Pass C compiler args to swiftc, notably -std=...
+        try:
+            c_langs = ['objc', 'c']
+            c_lang = next(iter(lang for lang in c_langs if lang in target.compilers))
+            cc = target.compilers[c_lang]
+            args.extend(arg for c_arg in cc.get_option_compile_args(target, env, subproject) for arg in ['-Xcc', c_arg])
+        except StopIteration:
+            pass
+
+        return args
+
     def get_working_directory_args(self, path: str) -> T.Optional[T.List[str]]:
         if version_compare(self.version, '<4.2'):
             return None