The PKG_CONFIG_PATH is an environment variable so you need to add it before running qmake.
So set it through Projects > Build Settings > Build Environment in QtCreator or set it through terminal before running qmake manually in terminal.
Screen Shot 1401-02-05 at 13.30.41.png
Then add following lines in your .pro file:
mac { #if you need to specify PKG_CONFIG = /usr/local/bin/pkg-config } #someone says this need in some Qt versions but not need in my Qt 5.12.12 QT_CONFIG -= no-pkg-config CONFIG += link_pkgconfig PKGCONFIG += protobuf \ grpc \ grpc++I can't find a way to set environment variable in .pro file. Can you do it?