I'm posting this message because I had a hard time discovering (in these forums and in web searches and manual searches), a very simple plausible explanation for an error I was receiving. Hopefully, it will help someone avoid spending the time it took for me to get to this solution. The error I got was after running aclocal and followed by autoconf: autom4te: need GNU m4 1.4 or later: /usr/ccs/bin/m4 In my case running on SunOS, had two installs of m4 (multiple m4 installs). One was in /usr/ccs/bin and the other was a GNU verion in /usr/local/bin. If you did a "m4 --version" you would get the correct GNU m4 1.4 responding, as it is in the PATH environment first. Yet autoconf was picking up the older version in /usr/ccs/bin. If you did a "whereis m4" you get: m4: /usr/ccs/bin/m4 /usr/local/bin/m4 The PATH environment variable had no affect on this search ordering that the whereis command was using and apparently autoconf was using this same search ordering. But, by chance I discovered the m4 environment variable, that you can set to notify autoconf of which m4 to use (i.e. selecting m4). So I put: setenv M4 /usr/local/bin/m4 in my .cshrc and now autoconf picked the correct one that I wanted ... no more error. At least for me, it was hard for me to link that error message with this bit of, what should be, common knowledge. I hope it eases someones pain. :) John Ling