diff -up ./dlib/cmake_utils/dlib.pc.in.old ./dlib/cmake_utils/dlib.pc.in
--- ./dlib/cmake_utils/dlib.pc.in.old	2020-07-01 17:28:39.020626797 +0200
+++ ./dlib/cmake_utils/dlib.pc.in	2020-07-01 17:28:57.555572710 +0200
@@ -4,5 +4,6 @@ includedir=@CMAKE_INSTALL_FULL_INCLUDEDI
 Name: @PROJECT_NAME@
 Description: Numerical and networking C++ library
 Version: @VERSION@
-Libs: -L${libdir} -ldlib @pkg_config_dlib_needed_libraries@
+Libs: -L${libdir} -ldlib -lgif
+Libs.private: @pkg_config_dlib_needed_libraries@
 Cflags: -I${includedir} @pkg_config_dlib_needed_includes@