2.6.13-git3: build failure: sysctl_optmem_max

While trying to build a kernel with CONFIG_SYSCTL disabled, the following
error occurs:

  CC      net/ipv4/ip_sockglue.o
net/ipv4/ip_sockglue.c: In function `ip_setsockopt':
net/ipv4/ip_sockglue.c:622: error: `sysctl_optmem_max' undeclared (first use in
net/ipv4/ip_sockglue.c:622: error: (Each undeclared identifier is reported only
net/ipv4/ip_sockglue.c:622: error: for each function it appears in.)

It seems that sysctl_optmem_max is only available if CONFIG_SYSCTL is set.
However, ip_setsockopt makes unconditional usage of this variable.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core