World building problems

For some time now I cannot build world on a particular machine. The machine
started as 5.0-released and was updated (via cvsup) to 5-current when I had
the time. Recently, every buildworld stops with the following error:

[ A *lot* of similar lines snipped ]
/usr/src/lib/libedit/tty.c:153: error: `ED_QUOTED_INSERT' undeclared here
(not in a function)
/usr/src/lib/libedit/tty.c:153: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:153: error: (near initialization for
`tty_map[6].bind[0]')
/usr/src/lib/libedit/tty.c:153: error: `ED_QUOTED_INSERT' undeclared here
(not in a function)
/usr/src/lib/libedit/tty.c:153: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:153: error: (near initialization for
`tty_map[6].bind[1]')
/usr/src/lib/libedit/tty.c:153: error: `ED_UNASSIGNED' undeclared here (not
in a function)
/usr/src/lib/libedit/tty.c:153: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:153: error: (near initialization for
`tty_map[6].bind[2]')
/usr/src/lib/libedit/tty.c:153: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:153: error: (near initialization for
`tty_map[6].bind')
/usr/src/lib/libedit/tty.c:153: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:153: error: (near initialization for
`tty_map[6]')
/usr/src/lib/libedit/tty.c:156: error: `ED_UNASSIGNED' undeclared here (not
in a function)
/usr/src/lib/libedit/tty.c:156: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:156: error: (near initialization for
`tty_map[7].bind[0]')
/usr/src/lib/libedit/tty.c:156: error: `ED_UNASSIGNED' undeclared here (not
in a function)
/usr/src/lib/libedit/tty.c:156: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:156: error: (near initialization for
`tty_map[7].bind[1]')
/usr/src/lib/libedit/tty.c:156: error: `ED_UNASSIGNED' undeclared here (not
in a function)
/usr/src/lib/libedit/tty.c:156: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:156: error: (near initialization for
`tty_map[7].bind[2]')
/usr/src/lib/libedit/tty.c:156: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:156: error: (near initialization for
`tty_map[7].bind')
/usr/src/lib/libedit/tty.c:156: error: initializer element is not constant
/usr/src/lib/libedit/tty.c:156: error: (near initialization for
`tty_map[7]')
In file included from editline.c:21:
/usr/src/lib/libedit/vi.c: In function `vi_search_prev':
/usr/src/lib/libedit/vi.c:790: error: `ED_SEARCH_PREV_HISTORY' undeclared
(first use in this function)
/usr/src/lib/libedit/vi.c: In function `vi_search_next':
/usr/src/lib/libedit/vi.c:803: error: `ED_SEARCH_NEXT_HISTORY' undeclared
(first
/usr/src/lib/libedit/vi.c: In function `vi_repeat_search_prev':
/usr/src/lib/libedit/vi.c:836: error: `ED_SEARCH_PREV_HISTORY' undeclared
(first
/usr/src/lib/libedit/vi.c:837: error: `ED_SEARCH_NEXT_HISTORY' undeclared
(first
*** Error code 1

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

Stop in /usr/src/lib.
*** 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.

I tried deleting /usr/src and /usr/obj and cvsupping fresh source, but no
luck.

-- 
Every sufficiently advanced magic is indistinguishable from technology
   - Arthur C Anticlarke