Package **** was not found in the pkg-config search path.

Package ** was not found in the pkg-config search path.

Package grpc++ was not found in the pkg-config search path.
Perhaps you should add the directory containing `grpc++.pc'
to the PKG_CONFIG_PATH environment variable
No package 'grpc++' found

解决办法：

locate grpc++.pc

显示：

/home/oeasy/install/grpc/libs/opt/pkgconfig/grpc++.pc

将此文件拷贝到 /usr/lib/pkgconfig/ 目录下：

sudo cp -f /home/oeasy/install/grpc/libs/opt/pkgconfig/grpc++.pc /usr/lib/pkgconfig/

再次编译，问题解决。