On Thu, 8 Aug 2013 10:22:28 +1000 Stephen Rothwell <sfr@canb.auug.org.au>
wrote:
>
> More quick testing with an empty file: v3.9 is OK, v3.10 gives
> CONFIG_MODULES unset.

Bisecting gives:

cfa98f2e0ae956feca935573e977d7661a9561b9 is the first bad commit
commit cfa98f2e0ae956feca935573e977d7661a9561b9
Author: Yann E. MORIN <yann.morin.1998@free.fr>
Date:   Wed Apr 24 22:00:04 2013 +0200

    kconfig: do not override symbols already set
    
    For randconfig, if a list of required symbols is specified with
    KCONFIG_ALLCONFIG, such symbols do not "have a value" as per
    sym_has_value(), but have the "valid" flag set.
    
    Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>


And reverting that commit in v3.10 gives me CONFIG_MODULES=y.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au