Hi Emanoil,
I just double checked, libpkcs11-helper1-dev is a dependency in tdelibs
also in R14.1.0 (I did not remember that initially to be honest). It seems
strange you have such missing dependency, it appears to be in Debian
Package tracker.
https://tracker.debian.org/pkg/pkcs11-helper
https://packages.debian.org/stretch/libpkcs11-helper1-dev
Just completed a R14.1.0 tdelibs rebuild in buster, no issues.
Hope it helps.
Cheers
Michele
Also tdebindings depends on libpkcs11-helper1-dev.