Sets, subsets, syspkgs, and MK*

[Masao Uebayashi <uebayasi%tombi.co.jp@localhost>]

NetBSD provides MK* variables to enable / disable features.  Its definition
is unclear.  How is it different from USE_* or HAVE_*?

I think we should have a concept of "subsets".  Which is subset of "sets",
and superset of "syspkgs".  "Subsets" is also the unit of "conditional build";
if you do -V MKLVM=no, you don't build LVM and LVM files are not installed
into ${DESTDIR}.

If you look close at distrib/sets/lists/*/* you'll see lines like:

distrib/sets/lists/base/mi:
    220 ./sbin/ipf                                      base-ipf-root           
ipfilter
    221 ./sbin/ipppctl                                  base-netutil-root
    222 ./sbin/ispppcontrol                             base-obsolete           
obsolete
    223 ./sbin/lmcctl                                   base-obsolete           
obsolete
    224 ./sbin/lvm                                      base-lvm-root           
lvm

So I wonder; why line 220 and 224 have 3 columns.  Why not line 221?
220 (ipfilter) and 224 (lvm) supports conditional build.  221 does *not*
support.  Why not?  Because the way we support conditional build is hard to
maintain:

usr.sbin/Makefile:
     55 # IP Filter
     56 .if (${MKIPFILTER} != "no")
     57 SUBDIR+=ipf
     58 .endif

Such knowledges are scattered all around the tree.

I think we should concentrate these knowledges into a single place.  Maintain
build (sub) directory as a set for each "subsets".  We should be able to build
only "netutil", like "build.sh build_subsets="netutil".

This leads to a question how to deal with conditions across subsets like
MKDEBUGLIB:

distrib/sets/lists/base/mi:
   2241 ./usr/lib/i18n/libBIG5.a                        comp-i18n-lib
   2242 ./usr/lib/i18n/libBIG5_g.a                      -unknown-               
debuglib
        :
   2294 ./usr/lib/libasn1.a                             comp-krb5-lib           
kerberos
   2295 ./usr/lib/libasn1_g.a                           -unknown-               
debuglib,kerberos
   2296 ./usr/lib/libasn1_p.a                           comp-krb5-proflib       
profile,kerberos

Here which subsets should *_g.a belong to?

Probably MKDEBUGLIB should be just an alias to enable all MK*DEBUGLIB.
Actually those lib*_g.a files are not even subsets; subset of subsets.
Because you can't build only libBIG5_g.a or libasn1_g.a.  I haven't sorted
out these and don't have a good word to represent this.

Masao

-- 
Masao Uebayashi / Tombi Inc. / Tel: +81-90-9141-4635