Just tried to build current (*) and after a while it died with:

echo '#if HAVE_NBTOOL_CONFIG_H' > parse.c.1
echo '#include "nbtool_config.h"' >> parse.c.1
echo '#endif' >> parse.c.1
cat parse.c >> parse.c.1
mv parse.c.1 parse.c
#    create  lex/ccl.d
/usr/home/bryan/etc/src/NetBSD/current/src/obj/tooldir.NetBSD-2.0G-i386/bin/nbhost-mkdep -f ccl.d --     -I/usr/home/bryan/etc/src/NetBSD/current/src/tools/compat/obj -I/usr/home/bryan/etc/src/NetBSD/current/src/tools/compat/obj/include  -I/usr/home/bryan/etc/src/NetBSD/current/src/tools/lex/../compat -DHAVE_NBTOOL_CONFIG_H=1  -D_FILE_OFFSET_BITS=64  -I. -I/usr/home/bryan/etc/src/NetBSD/current/src/tools/lex/../../usr.bin/lex  /usr/home/bryan/etc/src/NetBSD/current/src/tools/lex/../../usr.bin/lex/ccl.c
In file included from /usr/home/bryan/etc/src/NetBSD/current/src/tools/compat/obj/config.h:114,
                 from /usr/home/bryan/etc/src/NetBSD/current/src/usr.bin/lex/flexdef.h:34,
                 from /usr/home/bryan/etc/src/NetBSD/current/src/usr.bin/lex/ccl.c:31:
/usr/home/bryan/etc/src/NetBSD/current/src/tools/compat/compat_defs.h:66:2: #error _NETBSD_SOURCE is *not* to be defined.

(*) using:

./build.sh -r -U -X $HOME/etc/src/NetBSD/current/xsrc -x -D $HOME/etc/src/NetBSD/current/DEST -R $HOME/etc/src/NetBSD/current/REL distribution sets

-bp
--