Even though POCO_UNBUNDLED is used on Linux (Ubuntu 15.10) to compile Poco on develop branch, the expat sources are compiled and linked in libPocoXML anyway.

Debian lintian reports:

E: libpoco-1.7-clavis: embedded-library usr/lib/libPocoXML.so.40: expat

The reason for that is in how SRCS variable is set in the CMakeLists.txt.

I will fix it and prepare a pull request.