What is the easiest way to create a virtual package in debian?

Solution 1:

Install and use the debian package named equivs.

... Another use is to circumvent dependency checking: by letting dpkg think a particular package name and version is installed when it isn't

man equivs-build

Solution 2:

Look up checkinstall; after building from source, it creates .deb packages that can be installed via dpkg, thereby creating an entry in the APT database.