--- configure.orig	2014-05-18 00:52:57.000000000 +0000
+++ configure
@@ -2158,6 +2158,9 @@ fi
       ac_GNATLIB=`cd $ac_GNATDIR; ls libgnat-*.dll | sed 's,lib,,;s,.dll,,'`
       OS_SPECIFIC_LINK_OPTIONS=-Wl,-L$ac_GNATDIR,-l$ac_GNATLIB
       ;;
+   *dragonfly*|*bsd*)
+      TARGET_LFLAGS="-lm"
+      ;;
    *darwin*)
       SO_EXT=.dylib
       if test x$CAN_BUILD_SHARED = xyes ; then