I sup'd the latest stuff from the 1.4 branch which includes the 
security fixes for recently announced vulnerabilities, and this 
happened:

cc  -O2 -msupersparc -Werror -Wall -Wstrict-prototypes 
-Wmissing-prototypes  -Wpointer-arith -Wno-main -mno-fpu -I. 
-I/sys/arch -I/sys -nostdinc -DSUN4M -DDIAGNOSTIC 
-DNMBCLUSTERS="0x2000" -DMAXUSERS=32 -D_KERNEL  -c 
/sys/kern/uipc_syscalls.c
/sys/kern/uipc_syscalls.c: In function `sockargs':
/sys/kern/uipc_syscalls.c:1037: `PAGE_SIZE' undeclared (first use in 
this function)
/sys/kern/uipc_syscalls.c:1037: (Each undeclared identifier is 
reported only once
/sys/kern/uipc_syscalls.c:1037: for each function it appears in.)
*** Error code 1

Stop.