iw: use pkg-config
iw: use pkg-config

this makes iw use pkg-config.

Signed-off-by: Johannes Berg <8398eb9892c5ab2ff439ca0b5e4b0706dd9ebef9@sipsolutions.net>

OSLL/iw,Distrotech/iw,ewa/iw-modified,cozybit/iw,bcopeland/android_iw,timduru/platform-external-iw,idor/iw,SoluMachines/external_iw,timduru/platform-external-iw,Distrotech/iw,idor/iw,bw-oss/iw,bw-oss/iw,greearb/iw-ct,chunyeow/iw,ewa/iw-modified,chunyeow/iw,CTU-IIG/802.11p-iw,TeamEOS/external_iw,greearb/iw-ct,TeamEOS/external_iw,cozybit/iw,CTU-IIG/802.11p-iw,bcopeland/android_iw,OSLL/iw,SoluMachines/external_iw