BOOTSTRAPCFLAGS="-DISC [-DISC30 | -DISC40] -DSYSV [-Di386]"
these two defines are necessary to build the release I don't know if the build will succeed for ISC versions prior than 3.x
are only for getting the ISC version and therefore set the HasSymLinks to Yes ('cause symbolic linking were only supported from Version 4.x using the S5L Filesystem)
If you could use long filenames, you could enable
the installation of expanded Manual Pages by including
#define ExpandManNames YES
inside xf86site.def.
A build on ISC 4.x only needs -DISC40 defined in the BOOTSTRAPCFLAGS ( -DISC30 will be included automatically ).
Note: due to some incompatibilities between ISC 4.0 and 4.1, the default
is to build for ISC4.0, even if you build on 4.1.
If you want to build only for 4.1 you should
set #define IscCompileVersion 410 inside your
host.def.
(the fchmod function isn't available on 4.0, so it won't compile, and binaries from 4.1 won't run cause of the unsupported System call The libraries build for 4.1 couldn't be used with 4.0 Systems, due to some functions not available on 4.0)
standard defines for SystemV Release3 on x86 platform. You don't need to explicitly define -Di386 because this is pre-defined in /lib/cpp.