Support Ubuntu 20.04 LTS (Focal Fossa)

[ESSEDIA]

Verifying archive integrity...  100%   All good.
Uncompressing DisplayLink Linux Driver 5.2.14  100%  
DisplayLink Linux Software 5.2.14 install script called: install
Distribution discovered: Ubuntu 20.04 LTS
Installing
Configuring EVDI DKMS module
Registering EVDI kernel module with DKMS
Building EVDI kernel module with DKMS
ERROR (code 3): Failed to build evdi/5.2.14. Consult /var/lib/dkms/evdi/5.2.14/build/make.log for details..

make.log:

DKMS make.log for evdi-5.2.14 for kernel 5.4.0-26-generic (x86_64)
gio 23 apr 2020, 10:41:26, CEST
make KBUILD_VERBOSE=1 SUBDIRS=/var/lib/dkms/evdi/5.2.14/build SRCROOT=/var/lib/dkms/evdi/5.2.14/build CONFIG_MODULE_SIG= -C /lib/modules/5.4.0-26-generic/build modules
make[1]: ingresso nella directory "/usr/src/linux-headers-5.4.0-26-generic"
make -f ./Makefile syncconfig
make -f ./scripts/Makefile.build obj=scripts/basic
rm -f .tmp_quiet_recordmcount
make -f ./scripts/Makefile.build obj=scripts/kconfig syncconfig
  flex -oscripts/kconfig/lexer.lex.c -L scripts/kconfig/lexer.l
/bin/sh: 1: flex: not found
make[3]: *** [scripts/Makefile.host:9: scripts/kconfig/lexer.lex.c] Error 127
make[3]: *** Attesa per i processi non terminati....
  bison -o scripts/kconfig/parser.tab.c --defines=scripts/kconfig/parser.tab.h -t -l scripts/kconfig/parser.y
/bin/sh: 1: bison: not found
make[3]: *** [scripts/Makefile.host:17: scripts/kconfig/parser.tab.h] Error 127
make[2]: *** [Makefile:594: syncconfig] Error 2
make[1]: *** [Makefile:704: include/config/auto.conf.cmd] Error 2
make[1]: uscita dalla directory "/usr/src/linux-headers-5.4.0-26-generic"
make: *** [Makefile:22: all] Error 2

also I have tried to install evdi-dkms from repository, but same output