[Bug libstdc++/50871] libstdc++ should be built with -Wpedantic and/or -Wsystem-headers

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50871

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> ---
Created attachment 42754
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42754&action=edit
patch to add -Weh-mismatch to handle this case

Since the main concern seems to be EH mismatch, how about this?