Unicode headers ends by defining the DONE symbol in a enum.
It can clash with other includes.
(For instance the httpd.h from apache who use `#define DONE -2`).
Both project should not declare such common symbols publicly but we have
to do with them anyway.
There is no more integrated build of dependencies in the build system.
Dependencies are discovered using pkg-config except for ctpp2 where there
is no pkg-config file.