How to install on Debian 11

root@debian:# cat /etc/debian_version
11.6

cd /usr/src

git clone https://github.com/sems-server/sems.git

cd sems

ln -s pkg/deb/buster/ ./debian

apt-get install debhelper devscripts flite1-dev libcurl4-openssl-dev libev-dev \
libevent-dev libhiredis-dev libmysqlcppconn-dev libspandsp-dev libspeex-dev \
libgsm1-dev libopus-dev libssl-dev libxml2-dev python-dev -y

Note, selecting 'python-dev-is-python2' instead of 'python-dev'

If you need codec G729:
apt-get install libbcg729-0 libbcg729-dev -y

And modify exclude_core_modules parameter in the Makefile.defs:
exclude_core_modules = g729 silk codec2 => exclude_core_modules = ivr silk codec2

Add flags in debian/rules (not sure if it is needed, but as is):
CPPFLAGS += -DHAVE_XMLRPCPP_SSL -DSEMS_USE_SPANDSP=yes -DSEMS_USE_LIBSAMPLERATE=yes -DSEMS_USE_ZRTP=NO -DSEMS_USE_MP3=yes -DSEMS_USE_ILBC=yes -DSEMS_USE_G729=yes -DSEMS_USE_OPUS=yes

comment packages in Build-Depends: in debian/control
#               python-dev
#               python-sip-dev

exclude python modules in debian/rules
EXCLUDED_MODULES=gateway examples mp3 twit ivr conf_auth mailbox pin_collect

dpkg-buildpackage -rfakeroot -us -uc

export PATH=$PATH:/usr/local/sbin:/usr/sbin:/sbin

dpkg -i libsems1-dev_1.7.0~dev_amd64.deb sems_1.7.0~dev_amd64.deb