This para is obsolete, first because nobody is using Solaris 7 anymore,
and second because if someone was, configure should catch the snprintf
buffer overrun problem automatically (since commit 9bed827b), and third
because this is incorrect advice about how to manually force use of
snprintf.c anyway, and has been so at least since commit 3bc6bdf3.
The lack of complaints about it reinforces the conclusion that Solaris 7
no longer exists in the wild; so I don't feel a need to insert correct
advice instead.