* The Impish package builds fine by adding --enable-tss-tss2 in d/rules and adding libtss2-dev to Build-Depends.
* libtss2-dev is in main in >=Focal.
* The configure flag enables some well-scoped sections of code via #ifdefs. However this is not something like a separate module: support for TSS2 is builtin in the strongswan tools.
* I didn't check but I imagine this requires a libtss2-* runtime dep.
Some more info for evaluating this:
* The Impish package builds fine by adding --enable-tss-tss2 in d/rules and adding libtss2-dev to Build-Depends.
* libtss2-dev is in main in >=Focal.
* The configure flag enables some well-scoped sections of code via #ifdefs. However this is not something like a separate module: support for TSS2 is builtin in the strongswan tools.
* I didn't check but I imagine this requires a libtss2-* runtime dep.