It seems that variable name was changed

f280c165 · Laurent Montel · b835a476 · f280c165
Commit f280c165 authored Aug 21, 2021 by Laurent Montel 😁
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -35,7 +35,7 @@ target_link_libraries(kubrick
    KF5::KIOCore
    KF5::XmlGui
    KF5KDEGames
-    ${OPENGL_gl_LIBRARY}
+    ${OPENGL_LIBRARY}
    ${OPENGL_glu_LIBRARY}
 )