This is an experimental build system.
For details see
http://www.crufty.net/sjg/docs/freebsd-meta-mode.htm.
Build commands can be seen from the top-level with:
.Dl make show-valid-targets
The build is driven by dirdeps.mk using
.Va DIRDEPS
stored in
Makefile.depend files found in each directory.
.Pp
The build can be started from anywhere, and behaves the same.
The initial instance of
.Xr make 1
recursively reads
.Va DIRDEPS
from
.Pa Makefile.depend ,
computing a graph of tree dependencies from the current origin.
Setting
.Va NO_DIRDEPS
skips checking dirdep dependencies and will only build in the current
and child directories.
.Va NO_DIRDEPS_BELOW
skips building any dirdeps and only build the current directory.
.Pp
This also utilizes the
.Va WITH_META_MODE
logic for incremental builds.
.Pp
The build hides commands executed unless
.Va NO_SILENT
is defined.
.Pp
Note that there is currently no mass install feature for this.
.Pp