Each system type that Postfix knows is identified by a unique
name. Examples: SUNOS5, FREEBSD4, and so on. When porting Postfix
to a new system, the first step is to choose a SYSTEMTYPE name for
the new system. You must use a name that includes at least the
major version of the operating system (such as SUNOS4 or LINUX2),
so that different releases of the same system can be supported
without confusion.
Add a case statement to the "makedefs" shell script in the
source code top-level directory that recognizes the new system
reliably, and that emits the right system-specific information.
Be sure to make the code robust against user PATH settings; if the
system offers multiple UNIX flavors (e.g. BSD and SYSV) be sure to
build for the native flavor, instead of the emulated one.
Add an "#ifdef SYSTEMTYPE" section to the central util/sys_defs.h
include file. You may have to invent new feature macro names.
Please choose sensible feature macro names such as HAS_DBM or
FIONREAD_IN_SYS_FILIO_H.
I strongly recommend against using "#ifdef SYSTEMTYPE" in
individual source files. While this may look like the quickest
solution, it will create a mess when newer versions of the same
SYSTEMTYPE need to be supported. You're likely to end up placing
"#ifdef" sections all over the source code again.
