libtool causing problems

libtool being bad for gpsd?  20:0:0 becomes 21 ???

/bin/sh ./libtool --tag=CXX --mode=link g++ -version-number 20:0:0 -o libgps.la -rpath /sw32/lib ais_json.lo gpsutils.lo geoid.lo\
 gpsdclient.lo gps_maskdump.lo hex.lo json.lo libgps_core.lo libgps_json.lo netlib.lo rtcm2_json.lo shared_json.lo strl.lo daemon\
.lo libgpsmm.lo -lm -lc   -lpthread
libtool: link: g++ -dynamiclib -Wl,-undefined -Wl,dynamic_lookup -o .libs/libgps.20.dylib  .libs/ais_json.o .libs/gpsutils.o .lib\
s/geoid.o .libs/gpsdclient.o .libs/gps_maskdump.o .libs/hex.o .libs/json.o .libs/libgps_core.o .libs/libgps_json.o .libs/netlib.o\
 .libs/rtcm2_json.o .libs/shared_json.o .libs/strl.o .libs/daemon.o .libs/libgpsmm.o   -lm -lc -lpthread    -install_name  /sw32/\
lib/libgps.20.dylib -compatibility_version 21 -current_version 21.0 -Wl,-single_module