Hmm,
On Linux Mint 21.3 newly installed on recently built system.
So, in my case, it has nothing to do with it being an older version of Linux Mint.
gdebi - get the Dependencies not satisfiable error
dpkg - dependency problems, leaving unconfigured...
But, dpkg did give clues as to what was missing:
Selecting previously unselected package lazarus-project.
(Reading database ... 631231 files and directories currently installed.)
Preparing to unpack lazarus-project_3.2.0-0_amd64.deb ...
Unpacking lazarus-project (3.2.0) ...
dpkg: dependency problems prevent configuration of lazarus-project:
lazarus-project depends on libgtk2.0-dev (>= 2.6.0); however:
Package libgtk2.0-dev is not installed.
lazarus-project depends on fpc-laz (= 3.2.2); however:
Package fpc-laz is not installed.
lazarus-project depends on fpc-src (= 3.2.2); however:
Package fpc-src is not installed.
dpkg: error processing package lazarus-project (--install):
dependency problems - leaving unconfigured
Processing triggers for gnome-menus (3.36.0-1ubuntu3) ...
Processing triggers for desktop-file-utils (0.26+mint3+victoria) ...
Processing triggers for mailcap (3.70+nmu1ubuntu1) ...
Processing triggers for shared-mime-info (2.1-2) ...
Processing triggers for man-db (2.10.2-1) ...
Errors were encountered while processing:
lazarus-project
=
So I will install those and try again.
Mark
edit: that fixed it