assimp: new package

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
----
Changes v1 -> v2:
  - use github helper (thanks to Jörg Krause)

Changes v2 -> v3:
  - add c++ dependency (suggested by Thomas Petazzoni)
  - fix linking problem with builtin zlib (linking code
    with/without '-fpic' compiled, see e.g. [2]), workaround by selecting
    buildroot zlib package (failure detected by Thomas Petazzoni [2])

[1] https://cmake.org/pipermail/cmake/2006-March/008482.html
[2] http://lists.busybox.net/pipermail/buildroot/2015-December/146859.html
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
diff --git a/package/Config.in b/package/Config.in
index ffd3207..a024d3d 100644
--- a/package/Config.in
+++ b/package/Config.in
@@ -829,6 +829,7 @@
 endmenu
 
 menu "Graphics"
+	source "package/assimp/Config.in"
 	source "package/atk/Config.in"
 	source "package/atkmm/Config.in"
 	source "package/bullet/Config.in"