Index: exo-0.6.2/exo/Makefile.am
===================================================================
--- exo-0.6.2.orig/exo/Makefile.am	2011-09-05 22:11:21.302991166 +0200
+++ exo-0.6.2/exo/Makefile.am	2011-09-05 22:26:13.416502894 +0200
@@ -105,7 +105,8 @@
 	$(GIO_LIBS)							\
 	$(GTK_LIBS)							\
 	$(LIBX11_LIBS)							\
-	$(LIBXFCE4UTIL_LIBS)
+	$(LIBXFCE4UTIL_LIBS)						\
+	-lm
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = exo-$(LIBEXO_VERSION_API).pc