Function Perl_reg_numbered_buff_fetch_flags 

pub unsafe fn Perl_reg_numbered_buff_fetch_flags(
    my_perl: *mut PerlInterpreter,
    re: *mut REGEXP,
    paren: I32,
    sv: *mut SV,
    flags: U32,
)

thx shim for crate::Perl_reg_numbered_buff_fetch_flags.