Since commit ec35e2621a9457, using --with-x-toolkit=no with
"./configure" leads to:

Activate.c: In function ‘XMenuActivate’:
Activate.c:618:3: error: ‘FALLTHROUGH’ undeclared (first use in this function)
  618 |   FALLTHROUGH;
      |   ^~~~~~~~~~~


Configured using:
 'configure --prefix=/usr/ --mandir=/usr/share/man/
 --infodir=/usr/share/info/ --with-x-toolkit=no --without-makeinfo
 --with-xpm --with-jpeg --with-tiff --with-gif --with-png --with-x
 --with-file-notification=inotify'


-- 
Torsten Bronger