autom4te: need GNU m4 1.4 or later: /usr/ccs/bin/m4

[jling]

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