Ignore old style declaration warnings in oniguruma/src/st.c. This was already ignored for MSFT, but newer versions of clang complain as well. Signed-off-by: Jake Garver <jake@nvidia.com> Reviewed-by: Nhi Pham <nhi@os.amperecomputing.com> Tested-by: Nhi Pham <nhi@os.amperecomputing.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>