TODO revision 1.3 
1o Emit everything (ioconf.*, Makefile, ...) per-attribute.
2
3o Generate modular(9) related information.  Especially module dependency.
4
5o Rename "interface attribute" to "bus".
6
7  Instead of
8
9	define	audiobus {}
10	attach	audio at audiobus
11
12  Do like this
13
14	defbus	audiobus {}
15	attach	audio at audiobus
16
17o Sort objects in more reasonable order.
18
19  Put machdep.ko in the lowest address.  uvm.ko and kern.ko follow.
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21  Kill alphabetical sort (${OBJS:O} in sys/conf/Makefile.inc.kern.
22
23  Use ldscript.  Do like this
24
25	.text :
26	AT (ADDR(.text) & 0x0fffffff)
27	{
28	  *(.text.machdep.locore.entry)
29	  *(.text.machdep.locore)
30	  *(.text.machdep)
31	  *(.text)
32	  *(.text.*)
33	  :
34
35  Kill linker definitions in sys/conf/Makefile.inc.kern.
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37o Differentiate "options" and "flags"/"params".
38
39  "options" enables features by adding *.c files (via attributes).
40
41  "flags" and "params" are to change contents of *.c files.  These don't add
42  *.c files to the result kernel, or don't build attributes (modules).
43
44o Make flags/params per attributes (modules).
45
46  Basically flags and params are cpp(1) #define's generated in opt_*.h.  Make
47  them local to one attributes (modules).  Flags/params which affects files
48  across attributes (modules) are possible, but should be discouraged.
49
50o Generate things only by definitions.
51
52  In the ideal dynamically modular world, "selection" will be done not at
53  compile time but at runtime.  Users select their wanted modules, by
54  dynamically loading them.
55
56  This means that the system provides all choices; that is, build all modules
57  in the source tree.  Necessary information is defined in the "definition"
58  part.
59
60o Split cfdata.
61
62  cfdata is pattern matching rules to enable devices at runtime device
63  auto-configuration.  It is pure data and can (should) be generated separately
64  from the code.
65