Swift: add -Wno-pragma-once-outside-header to check

Author: redsun82

swift/extractor/infra/file/BUILD.bazel

@@ -18,7 +18,8 @@ genrule(
     # see if https://cplusplus.github.io/LWG/issue3657 is fixed with the current compiler or not
     # if fixed, PathHash.h.workaround will not compile
     cmd = "\n".join([
-        "if $(CC) -c -x c++ -std=c++17 $(rootpath PathHash.h.workaround) -o /dev/null &> /dev/null; then",
+        "if $(CC) -c -x c++ -std=c++17 -Wno-pragma-once-outside-header \\",
+        "    $(rootpath PathHash.h.workaround) -o /dev/null &> /dev/null; then",
         "  cp $(rootpath PathHash.h.workaround) $@",
         "else",
         "  cp $(rootpath PathHash.h.fixed) $@",

swift/extractor/infra/file/PathHash.h.workaround

@@ -10,7 +10,8 @@
 // std::variant would not kick in (we use std::filesystem::path in a variant used as a map key).
 namespace std {
 template <>
-struct std::hash<std::filesystem::path> {
-  std::size_t operator()(const std::filesystem::path& path) const { return hash_value(path); }
+struct hash<filesystem::path> {
+  size_t operator()(const filesystem::path& path) const { return hash_value(path); }
 };
+
 }  // namespace std