m4_dnl To avoid annoying conflicts with quote characters, use
m4_dnl U+2068 FIRST STRONG ISOLATE and U+2069 POP DIRECTIONAL ISOLATE
m4_changequote(⁨,⁩)

m4_dnl We also need to avoid the comment character ever doing absolutely
m4_dnl anything, so set it to U+FFFD REPLACEMENT CHARACTER
m4_changecom(�)