Warning was:
/usr/include/x86_64-linux-gnu/qt5/QtGui/qopenglext.h:60: warning: "GL_GLEXT_VERSION" redefined
#define GL_GLEXT_VERSION 20170325
/usr/include/GL/glext.h:54: note: this is the location of the previous definition
#define GL_GLEXT_VERSION 20180725