Thank you very much for the patch! I have picked up your Debian specific changes into the Debian mirror as https://salsa.debian.org/pberndt-guest/pqiv/commit/84ce4837730d8d7d48283519b9f2983b9b56c57d
The patch to the makefile (which uses GNU specific features of make, hence the name) is applied upstream. If that's alright with you I'll wait for the next release before bumping the Debian package. It will include this change, but is blocked on https://github.com/phillipberndt/pqiv/issues/130. Expect a couple of weeks.
