CVS broken - large file support?

On FreeBSD/Alpha, CVS gives:

gmake[4]: Entering directory `/home/chriskl/pgsql-head/src/backend/parser'
gmake[4]: Nothing to be done for `all'.
gmake[4]: Leaving directory `/home/chriskl/pgsql-head/src/backend/parser'
gcc -pipe -O -g -Wall -Wmissing-prototypes -Wmissing-declarations -I../../..
/src/interfaces/libpq -I../../../src/include   -c -o common.o common.c -MMD
In file included from common.c:21:
pg_backup_archiver.h:168: syntax error before `off_t'
gmake[3]: *** [common.o] Error 1
gmake[3]: Leaving directory `/home/chriskl/pgsql-head/src/bin/pg_dump'
gmake[2]: *** [all] Error 2
gmake[2]: Leaving directory `/home/chriskl/pgsql-head/src/bin'
gmake[1]: *** [all] Error 2
gmake[1]: Leaving directory `/home/chriskl/pgsql-head/src'
gmake: *** [all] Error 2

Chris