Today I tried to compile ZNC 1.6.5 from source (.tar.gz) which I got from their releases on Github. Without checking their installation instruction first, I dove right in. After a quick ./autogen.sh I was happily underway and after quick configure I turned to make and it surprised me with the following gem:
Packing man page znc.1.gz... Packing man page znc-buildmod.1.gz... It looks like git submodules are not initialized. Run: git submodule update --init --recursive Makefile:167: recipe for target 'third_party/Csocket/Csocket.h' failed make: *** [third_party/Csocket/Csocket.h] Error
The reason I chose the tarball was because I wanted to use a release, on a system which does not have git installed. After a quick chat on their friendly Freenode IRC channel, they pointed me to their own tarball including installation instruction. Immediately I noticed the difference in size (and thus MD5SUM) and the autogen.sh was gone. This worked like a charm!
Note to self: do not assume tarballs from Github always work and check the official documentation _first_