CLANG; still cc in use when building the WORLD with CLANG?

[Hartmann, O.]

On 08/30/11 19:58, Dimitry Andric wrote:
> On 2011-08-30 18:44, Alex Kuster wrote:
>> Thanks for pointing out those details !
>> This whole thing about make.conf&  src.conf is very confusing and 
>> gives the
>> impression of something half ported ...
>
> The only thing that is "half ported" at the moment, is an easy "use
> clang to build world" switch.  This will be properly addressed after 9.0
> is released.  As to the make.conf/src.conf confusion, it is very simple
> really:
>
> - make.conf is used for system-wide settings, applied to every build
>   using make.
>
> - src.conf is used for setting FreeBSD source tree settings, which are
>   always of the form WITH_XXX or WITHOUT_XXX.  See src.conf(5) for a
>   full list.  Any other "make" settings, such as CC, CFLAGS, etc, are
>   better specified in make.conf, though the manpage does not tell you
>   so explicitly.

This is as I understood the manpage of src.conf. There is only a YES/set 
and NO/unset.

Well, I might be wrong, but FreeBSD separates strictly the core 
operating system and the ports stuff.
When it came to CLANG compiled core system and I read about src.conf, my 
intuitive thinking was that
this is the long awaited separation from having everything mixed in 
/etc/make.conf (by the way, somehow
I feel I would all the ports stuff, even it make.conf, looking for at 
/usr/local/etc/make.conf ...).

>
> Now, why do some settings, such as CFLAGS, in src.conf not always work
> correctly?  Because src.conf is only read when bsd.own.mk is included
> (implicitly or explicitly) in a Makefile, and this is *not* always done
> at the start of the file.
>
> On the other hand, make.conf is read from /usr/share/sys.mk, which is
> automatically included before anything else is done.
>
> Take, for example, the Makefile for cp(1), in /usr/src/bin/cp (I
> prefixed line numbers for reference):
>
> 1: #       @(#)Makefile    8.1 (Berkeley) 5/31/93
> 2: # $FreeBSD: head/bin/cp/Makefile 192586 2009-05-22 15:56:43Z trasz $
> 3:
> 4: PROG=   cp
> 5: SRCS=   cp.c utils.c
> 6: CFLAGS+= -DVM_AND_BUFFER_CACHE_SYNCHRONIZED -D_ACL_PRIVATE
> 7:
> 8: .include <bsd.prog.mk>
>
> At line 1, make will already have read make.conf, picking up settings
> from it.  Suppose it picks up "CFLAGS=-foo".
>
> At line 6, CFLAGS has several flags appended.  Its value will then
> become "-foo -DVM_AND_BUFFER_CACHE_SYNCHRONIZED -D_ACL_PRIVATE".
>
> At line 8, bsd.prog.mk is read, which (through bsd.own.mk) belatedly
> reads src.conf.  If you have a setting such as "CFLAGS=-bar" in it, this
> value will *override* the previous one, possibly having disastrous
> consequences.

Great! Many thanks, this is a nice explanation. With such detailed info 
it's a bit
easier to hunt down the mistakes I made for my own.

Thanks again.

Oliver