Am 24.06.2022 um 13:23 schrieb ESTEVEZ NUÑEZ JUAN CARLOS:
 It occurs to me to test if the problem arises with an also fresh
update
 in Ubuntu.
 Unfortunately, I can´t as since some days the 'make' command stops
 waiting for
 an answer after the message /! Missing $ inserted/.
 (I build all the gretl updates, following appendix B of Users Guide over
 the last years)
 Don´t know if this may be related. 
Juan Carlos, I guess you have resolved this particular issue in the
meantime. It sounds as if it's coming from TeX while compiling the
documentation. I would simply try to do "make clean" and then starting over.
cheers
sven