Support for DragonFly BSD

Mapped to NetBSD, the closest existing match.  (Even though DragonFly
BSD is derived from FreeBSD, the shared library version numbering
matches NetBSD, and the rest is mostly the same among all BSD
variants.)

per "Rumko"

configure

@@ -2194,6 +2194,7 @@ case $host_os in
     bsdi*) template=bsdi ;;
   cygwin*) template=cygwin ;;
   darwin*) template=darwin ;;
+dragonfly*) template=netbsd ;;
     dgux*) template=dgux ;;
  freebsd*) template=freebsd ;;
     hpux*) template=hpux ;;

configure.in

@@ -58,6 +58,7 @@ case $host_os in
     bsdi*) template=bsdi ;;
   cygwin*) template=cygwin ;;
   darwin*) template=darwin ;;
+dragonfly*) template=netbsd ;;
     dgux*) template=dgux ;;
  freebsd*) template=freebsd ;;
     hpux*) template=hpux ;;