Add pkg-config as build dep so libusb can be found on osx.
@@ -21,6 +21,7 @@ requirements:
# libudev is on its own in CentOS 6, packaged with systemd in CentOS 7
- {{ cdt('libudev-devel') }} # [linux and cdt_name=='cos6']
- ninja
+ - pkg-config
host:
- fftw
- libusb
