libgxpstools must be linked to libm, otherwise there will be missing symbols.

--- tools/Makefile.in.orig	2012-01-04 16:42:56.658571930 +0100
+++ tools/Makefile.in	2012-01-04 16:43:21.591967795 +0100
@@ -500,7 +500,7 @@ clean-noinstLTLIBRARIES:
 	  rm -f "$${dir}/so_locations"; \
 	done
 libgxpstools.la: $(libgxpstools_la_OBJECTS) $(libgxpstools_la_DEPENDENCIES) 
-	$(AM_V_CCLD)$(libgxpstools_la_LINK)  $(libgxpstools_la_OBJECTS) $(libgxpstools_la_LIBADD) $(LIBS)
+	$(AM_V_CCLD)$(libgxpstools_la_LINK)  $(libgxpstools_la_OBJECTS) $(libgxpstools_la_LIBADD) -lm $(LIBS)
 install-binPROGRAMS: $(bin_PROGRAMS)
 	@$(NORMAL_INSTALL)
 	test -z "$(bindir)" || $(MKDIR_P) "$(DESTDIR)$(bindir)"
