[LAU] qtractor does not build lv2 external ui

Hello, I am trying to build qtractor with proper lV2-support (all distropackages I tried, froze on listing LV2) I have installed slv2 from http://drobilla.net/blog/software/slv2/ but alas! waf configure tells me: checking for slv2.h... yes checking lv2_event.h usability... no checking lv2_event.h presence... no checking for lv2_event.h... no checking lv2_event_helpers.h usability... no checking lv2_event_helpers.h presence... no checking for lv2_event_helpers.h... no checking lv2_uri_map.h usability... no checking lv2_uri_map.h presence... no checking for lv2_uri_map.h... no configure: WARNING: *** LV2 event extension will be disabled. LV2 Plug-in support (libslv2) . . . . . . . . . .: yes LV2 Plug-in Event/MIDI support . . . . . . . . . .: no LV2 Plug-in External UI support . . . . . . . . .: no LV2 Plug-in Save/Restore support . . . . . . . . .: no what can I do?