Install libsfobjc-7-dev-armhf-cross by entering the following commands in the terminal:
sudo apt update sudo apt install libsfobjc-7-dev-armhf-cross
Description:
Runtime library for GNU Objective-C applications (soft float development files)
This package contains the headers and static library files needed to build GNU ObjC applications.
Homepage: http://gcc.gnu.org/
Version: 7.3.0-16ubuntu3cross1
Section: universe/libdevel