Tectonic falls with \usepackage{gregoriotex}

v. 0.15

test.tex:
```
% !TEX TS-program = LuaLaTeX+se
% !TEX encoding = UTF-8

\documentclass[12pt]{article}

\usepackage{gregoriotex}

\begin{document}
Test
\end{document}
```

Output is:
```
❯ tectonic test.tex
Running TeX ...
error: terminal input forbidden
```
