I faced this issue on ubuntu 14.04 and 16.04. To fix this issue, install libicu-dev then try installing again. I did
$sudo apt install libicu-dev
$pip install pyicu
I faced this issue on ubuntu 14.04 and 16.04. To fix this issue, install libicu-dev then try installing again. I did
$sudo apt install libicu-dev
$pip install pyicu