aclocal 1.9.5 is generating the following warning for gtkglarea 1.2.3-r1: /usr/share/aclocal/gtkgl.m4:4: warning: underquoted definition of AM_PATH_GTKGL
Created attachment 58594 [details, diff] patch fixes the warning
These are harmless warnings for unmaintained old versions and patching would just be a lot of effort for no gain.