If -DBUILTIN_CHANNELS=OFF is supplied to cmake, auxiliary channel modules
are built as plugins, that are loaded from $LIBDIR/freerdp as shared libs.
This patch fixes the linkage of these plugins by taking inter-channel dependencies
of this separation into account. If BUILTIN_CHANNELS=ON, these channel modules
are linked directly into the main modules. Therefore, the linking of the plugins
is conditioned accordingly.
297f965052