Today's UNIX like operating systems have some minor differences. In general there are two recommendations overall to prevent trouble:
Still, this is not a MUST, but highly recommended. On binary distributions make sure the devel packages are installed and header/libraries files are available (e.g. openssl). If you still run into trouble see some hints for your operating system below.
eQmail 1.09 is tested to compile and run on the following systems:
qbiff is removed!
/var is mounted with nosuid by default
OpenBSD doesn't provide the UNIX standard crypt function. It have to be installed from the source package.