This will generate dependencies rather than depending on the previous behavior
of depending on the guessed OBJS: *.h dependecies or a user running
'make depend'.
Experimentation showed that depending only on headers was not enough and
prone to .ORDER errors. Downstream users may also have added
dependencies into beforedepend or afterdepend targets. The safest way to
ensure dependencies are generated before build is to run 'make depend'
beforehand rather than just depending on DPSRCS+SRCS.
Note that the OBJS_DEPEND_GUESS mechanism (a.k.a .if !exists(.depend) then
foo.o: *.h) is still useful as it improves incremental builds with missing
.depend.* files and allows 'make foo.o' to usually work, while this
'beforebuild: depend' ensures that the build will always find all dependencies.
The 'make foo.o' case has no means of a 'beforebuild' hook.
This also removes several hacks in the DIRDEPS_BUILD:
- NO_INSTALL_INCLUDES is no longer needed as it mostly was to work around
.ORDER problems with building the needed headers early.
- DIRDEPS_BUILD: It is no longer necesarry to track "local dependencies" in
Makefile.depend.
These were only in Makefile.depend for 'clean builds' since nothing would
generate the files due to skipping 'make depend' and early dependency
bugs that have been fixed, such as adding headers into SRCS for the
OBJS_DEPEND_GUESS mechanism. Normally if a .depend file does not exist then
a dependency is added by bsd.lib.mk/bsd.prog.mk from OBJS: *.h. However,
meta.autodep.mk creates a .depend file from created meta files and inserts
that into Makefile.depend. It also only tracks *.[ch] files though which can
miss some dependencies that are hooked into 'make depend'. This .depend
that is created then breaks incremental builds due to the !exists(.depend)
checks for OBJS_DEPEND_GUESS. The goal was to skip 'make depend' yet it only
really works the first time. After that files are not generated as expected,
which r288966 tried to address but was using buildfiles: rather than
beforebuild: and was reverted in r291725. As noted previously,
depending only on headers in beforebuild: would create .ORDER errors
in some cases.
meta.autodep.mk is still used to generate Makefile.depend though via:
gendirdeps: Makefile.depend
.END: gendirdeps
This commit allows removing all of the "local dependencies" in
Makefile.depend which cuts down on churn and removes some of the
arch-dependent Makefile.depend files.
The "local dependencies" were also problematic for bootstrapping.
Sponsored by: EMC / Isilon Storage Division
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