--- configure.ac.orig	2017-06-02 13:20:16 UTC
+++ configure.ac
@@ -30,9 +30,6 @@ AC_DEFINE_UNQUOTED(GETTEXT_PACKAGE, "$GETTEXT_PACKAGE"
 case "$host_os" in
 freebsd*)
 # Using clang:
-  CC=clang40
-  CPP=clang-cpp40
-  CXX=clang++40
 # or gcc5:
 #  CC=gcc5
 #  CPP=cpp5
@@ -52,9 +49,12 @@ AC_TYPE_SSIZE_T
 dnl check for installed clipperlib newer than 5.1.0 (has PolyNode)
 AC_DEFINE([HAVE_CLIPPERLIB],[0],[Have external clipper])
 CLIPPER_LIBS="libclipper.la"
+saved_LIBS=$LIBS
+LIBS="-lpolyclipping $LIBS"
 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <polyclipping/clipper.hpp>], [ClipperLib::PolyNode cnode])],
     [AC_DEFINE([HAVE_CLIPPERLIB],[1]) CLIPPER_LIBS="-lpolyclipping"],
     [AC_MSG_WARN([libclipper is not installed. Using internal copy.])])
+LIBS=$saved_LIBS
 AC_SUBST(CLIPPER_LIBS)