I noticed this because alpha was broken due to the recent commit commit
bdc80787 ("avoid overflows in
kernel/time.c").  Most arches do something like this in their
asm/param.h:

#ifdef __KERNEL__
# define HZ CONFIG_HZ
#else
# define HZ 100
#endif

A few arches though (namely alpha/h8300/um/v850/xtensa) either do no set
HZ at all for !__KERNEL__, or they set it wrongly.  This should bring all
arches in line by setting up HZ for userspace.

Without this currently perl 5.10 doesn't build on alpha:

perl.c: In function 'perl_construct':
perl.c:388: error: 'CONFIG_HZ' undeclared (first use in this function)
-> http://buildd.debian.org/fetch.cgi?pkg=perl;ver=5.10.0-10;arch=alpha;stamp=1210252894Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: maximilian attems <max@stro.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ HZ on alpha is 1024 for historical reasons.  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>