On MacOS 10.4.3 
./bootstrap --prefix=/Users/schwarz/pkg --pkgdbdir=/Users/schwarz/pkg/db --varbase=/Users/schwarz/pkg/var --ignore-case-check --ignore-user-check

fails like this:

gcc -O2  -I. -I/Users/schwarz/pkgsrc/pkgsrc/bootstrap/work/bmake -DHAVE_CONFIG_H  -I../../libnbcompat "-D_PATH_DEFSYSPATH=\"/Users/schwarz/pkg/share/mk:/usr/share/mk:/usr/local/share/mk:/opt/share/mk\""  -DMAKE_NATIVE  -DSIGNAL_FLAGS=SA_RESTART  -c /Users/schwarz/pkgsrc/pkgsrc/bootstrap/work/bmake/sigcompat.c
bmake.boot: don't know how to make /usr/lib/libc.a. Stop

bmake.boot: stopped in /Users/schwarz/pkgsrc/pkgsrc/bootstrap/work/bmake/Darwin
make: *** [bootstrap] Error 2

if anyone has a fix, please let me know.

-- 
Georg Schwarz    http://home.pages.de/~schwarz/
 georg.schwarz@freenet.de  +49 178 8545053