How to Type ƛ on IPA Gboard?

I work with languages that use Americanist Phonetic Notation. It's similar enough to the International Phonetic Notation that Gboard's IPA layout can type all the characters I need *except* barred lambda. Is there some way to add a bar or strike through to a character within Gboard? It would be very convenient not to have to switch to a separate app to write these languages.