CVS HEAD compile failure on Freebsd 4.9

Fresh checkout of CVS HEAD yesterday, updated today :

$ ./configure --prefix=/usr/local/pgsql/7.5
$ make
gmake[4]: Entering directory
`/usr/home/postgres/develop/c/pgsql/src/backend/access/nbtree'
gcc -O2 -fno-strict-aliasing -Wall -Wmissing-prototypes
-Wmissing-declarations -I../../../../src/include -c -o nbtree.o nbtree.c
nbtree.c: In function `btbulkdelete':
nbtree.c:600: storage size of `_delay' isn't known
nbtree.c:600: warning: implicit declaration of function `select'
nbtree.c:600: warning: unused variable `_delay'
nbtree.c:602: storage size of `_delay' isn't known
nbtree.c:602: warning: unused variable `_delay'
gmake[4]: *** [nbtree.o] Error 1
gmake[4]: Leaving directory
`/usr/home/postgres/develop/c/pgsql/src/backend/access/nbtree'
gmake[3]: *** [nbtree-recursive] Error 2
gmake[3]: Leaving directory
`/usr/home/postgres/develop/c/pgsql/src/backend/access'
gmake[2]: *** [access-recursive] Error 2
gmake[2]: Leaving directory `/usr/home/postgres/develop/c/pgsql/src/backend'
gmake[1]: *** [all] Error 2
gmake[1]: Leaving directory `/usr/home/postgres/develop/c/pgsql/src'
gmake: *** [all] Error 2
*** Error code 2

$ uname -a
FreeBSD spiney 4.9-RELEASE FreeBSD 4.9-RELEASE #3

kernel customizations : i686 (i.e 386->586 de-selected for kernel build)