There was a bug in the c_src/Makefile that caused the decompression and
renaming of the directory in the tar file with the C dependencies to happen
every time the project was built. The bug was experienced as a build
failure when recompiling for the third time. The error that was shown was:
mv: cannot move ‘zeromq-3.2.2’ to ‘zeromq3/zeromq-3.2.2’: Directory not empty
This was happening because the untarred directory's (zeromq3) date in the
filesystem was older than the one from the tar file (zeromq-3.2.2.tar.gz).
This was discovered by debugging the make process and seeing this message:
Prerequisite `../deps/zeromq-3.2.2.tar.gz' is newer than target `../deps/zeromq3'.
Must remake target `../deps/zeromq3'.
The problem was fix by avoiding chained targets in the Makefile.