dnl FreeBSD -pthread check - Jonathan McDowell
AC_DEFUN(AC_PTHREAD_FREEBSD,
         [AC_MSG_CHECKING([if we need -pthread for threads])
          AC_CACHE_VAL(ac_ldflag_pthread,
                       [ac_save_LDFLAGS="$LDFLAGS"
                        LDFLAGS="-pthread $LDFLAGS"
                        AC_TRY_LINK([char pthread_create();],
                                    pthread_create();,
                                    eval "ac_ldflag_pthread=yes",
                                    eval "ac_ldflag_pthread=no"),
                                    LIBS="$ac_save_LDFLAGS"
                       ])
          if eval "test \"`echo $ac_ldflag_pthread`\" = yes"; then
            AC_MSG_RESULT(yes)
          else
            AC_MSG_RESULT(no)
          fi
         ])