Or even

```c
if (Z_STRVAL_P(header_name) == IS_STRING && !memchr(Z_STRVAL_P(header_name), ':', Z_STRLEN_P(header_name))) {
    phalcon_call_method_p1_noret(headers, "remove", header_name);
}
```

That is, if `:` is not found in the header, kill that header.