Error linking custom Qt Creator plugin with other plugins

[Evolix]

I have the case that I have to use some objects and classes from the Project Explorer plugin in my own plugin.
I added the dependency in the pro file, but the project cannot link.

The problem : The error is an undefined reference to the staticMetaObject of classes I require.

What I have :

• I fully recompiled Qt 5.4 and Qt Creator 3.6.1, so I have all the files required (no?).
• I use the Qt 5.4 recompiled kit to build my Qt Creator plugin (so it's compatible to my newly compiled Qt Creator if I'm not mistaken).

What I tried (apart from building the project from Qt Creator) :

• I ran nm libProjectExplorer.so | grep "staticMetaObject" and check that the symbols really existed (and yes).
• I also checked that the plugin shared library is given to the linker.

The question : I don't know what I'm missing here, does someone have any ideas ?

PS: This is my first plugin for Qt Creator. Before adding ProjectExplorer the project built normally.