buildworld inside a jail

Hello,

with identical (5.2-p2) sources I can buildworld on the host machine but if I 
try to buildowrld inside a jail it fails with the following error:

gzip -cn /usr/src/lib/libz/zlib.3 > zlib.3.gz
===> libexec
===> libexec/atrun
cc -O -pipe -mcpu=pentiumpro -DATJOB_DIR=\"/var/at/jobs/\"  -DLFILE=\"/var/at/
jobs/.lockfile\"  -DLOADAVG_MX=1.5 -DATSPOOL_DIR=\"/var/at/spool\"  
-DVERSION=\"2.9\" -DDAEMON_UID=1 -DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  
-DDEFAULT_AT_QUEUE=\'c\' -DPERM_PATH=\"/var/at/\" -I/usr/src/libexec/
atrun/../../usr.bin/at -I/usr/src/libexec/atrun  -c /usr/src/libexec/atrun/
atrun.c
cc -O -pipe -mcpu=pentiumpro -DATJOB_DIR=\"/var/at/jobs/\"  -DLFILE=\"/var/at/
jobs/.lockfile\"  -DLOADAVG_MX=1.5 -DATSPOOL_DIR=\"/var/at/spool\"  
-DVERSION=\"2.9\" -DDAEMON_UID=1 -DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  
-DDEFAULT_AT_QUEUE=\'c\' -DPERM_PATH=\"/var/at/\" -I/usr/src/libexec/
atrun/../../usr.bin/at -I/usr/src/libexec/atrun  -c /usr/src/libexec/atrun/
gloadavg.c
cc -O -pipe -mcpu=pentiumpro -DATJOB_DIR=\"/var/at/jobs/\"  -DLFILE=\"/var/at/
jobs/.lockfile\"  -DLOADAVG_MX=1.5 -DATSPOOL_DIR=\"/var/at/spool\"  
-DVERSION=\"2.9\" -DDAEMON_UID=1 -DDAEMON_GID=1  -DDEFAULT_BATCH_QUEUE=\'E\'  
-DDEFAULT_AT_QUEUE=\'c\' -DPERM_PATH=\"/var/at/\" -I/usr/src/libexec/
atrun/../../usr.bin/at -I/usr/src/libexec/atrun   -o atrun atrun.o gloadavg.o
/usr/obj/usr/src/i386/usr/lib/libc.so: undefined reference to `_nsyyerror'
/usr/obj/usr/src/i386/usr/lib/libc.so: undefined reference to `_nsyylex'
/usr/obj/usr/src/i386/usr/lib/libc.so: undefined reference to `_nsyyin'
/usr/obj/usr/src/i386/usr/lib/libc.so: undefined reference to `_nsyylineno'
/usr/obj/usr/src/i386/usr/lib/libc.so: undefined reference to `_nsyytext'
*** Error code 1

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

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

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

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

Stop in /usr/src.

Any idea?

Thanks in advance,

-Harry