Installed zita-dpl1 on my other UbuntuStudio 18.04 PC and figured for completeness I'd document what needed to be installed or was already there.
Added libxft-dev then did the make for clxclient-3.9.0 and clthreads-2.4.0.
not the rev 3.6.1 listed in the INSTALL file in the zita-dpl1-0.1.0 directory.)
On this pc libjack-jackd2-dev was already there, but to get zita-dpl1 to compile/make needed add libcairo2-dev to get cairo.h
Note: I couldn't find libjack-jack2-dev, is there a typo in the name (missing 'd')?
All seems to be good. :)
Thanks,
Mac