Install libgnustep-gui-dev by entering the following commands in the terminal:
sudo apt update sudo apt install libgnustep-gui-dev
Description:
GNUstep GUI header files and static libraries
The GNUstep GUI Library is a powerful library of graphical user interface classes written completely in the Objective-C language; the classes are based upon the OpenStep specification, and provide the user with a traditional nextstep-like look and feel. . This package contains the header files and static libraries required to build applications against the GNUstep GUI library. . Install this package if you wish to develop your own programs using the GNUstep GUI Library.
Homepage: http://gnustep.org
Version: 0.26.2-3
Section: universe/libdevel