doesn't detect gnuradio installed on Arch

[gbin]

after #2:
./configure

checking for GNURADIO_CORE... configure: error: Package requirements (gnuradio-core >= 3) were not met:

No package 'gnuradio-core' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables GNURADIO_CORE_CFLAGS
and GNURADIO_CORE_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.

if I set where my gnuradio libs are with:
GNURADIO_CORE_LIBS=/usr/lib ./configure

it does the same thing,