psi-plugins is a small collection of LV2 plugins ideal for (but not limited to) electronic music. It uses the ntk widget library (possibly provided by your distribution as non-ntk-devel/ntk-dev)
They are:
super_welle: a 4 oscillator / 16 voice virtual analog unison synthesizer
midi_gate: an enveloped stereo MIDI gate
sidechain_gate: stereo sidechain gate (with hysteresis) based on Steve Harris's Gate plugin
midi_rnd: MIDI randomizer. Randomize incoming MIDI within a range, or relative within an octave range.
./waf configure
./waf
sudo ./waf install
To specify a custom prefix and/or LV2 directory:
./waf configure --prefix=/usr --lv2dir=/usr/lib64/lv2
./waf
sudo ./waf install