I'm getting the following warning from aclocal 1.9.5 when it runs through libsigc++ 1.0.4-r2: /usr/share/aclocal/sigc++.m4:8: warning: underquoted definition of AM_PATH_SIGC
Created attachment 58565 [details, diff] patch patch that fixes the warning
These are harmless warnings for unmaintained old versions and patching would just be a lot of effort for no gain.