cant build world

[Petr Janda]

In file included from 
/usr/obj/usr/src/world_i386/usr/include/sys/signal.h:261,
                from 
/usr/obj/usr/src/world_i386/usr/include/sys/select.h:44,
                from 
/usr/obj/usr/src/world_i386/usr/include/sys/types.h:196,
                from 
/usr/obj/usr/src/world_i386/usr/include/machine/tls.h:38,
                from 
/usr/src/gnu/lib/gcc34/csu/../../../../lib/csu/i386/crt1.c:33:
/usr/obj/usr/src/world_i386/usr/include/sys/ucontext.h:32:1: 
unterminated #ifndef
In file included from 
/usr/obj/usr/src/world_i386/usr/include/sys/signal.h:261,
                from 
/usr/obj/usr/src/world_i386/usr/include/sys/select.h:44,
                from 
/usr/obj/usr/src/world_i386/usr/include/sys/types.h:196,
                from 
/usr/src/gnu/lib/gcc34/csu/../../../usr.bin/cc34/cc_tools/../../../../contrib/gcc-3.4/gcc/tsystem.h:82,
                from 
/usr/src/gnu/lib/gcc34/csu/../../../usr.bin/cc34/cc_tools/../../../../contrib/gcc-3.4/gcc/crtstuff.c:62:
/usr/obj/usr/src/world_i386/usr/include/sys/ucontext.h:32:1: 
unterminated #ifndef
mkdep: compile failed
*** Error code 1

Stop in /usr/src/gnu/lib/gcc34/csu.
*** Error code 1
Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.