diff -up ./gegl/buffer/Makefile.am.orig ./gegl/buffer/Makefile.am
--- ./gegl/buffer/Makefile.am.orig	2016-01-23 10:28:49.244165206 +0200
+++ ./gegl/buffer/Makefile.am	2016-01-23 10:26:30.950468279 +0200
@@ -83,3 +83,4 @@ libbuffer_la_SOURCES = \
     gegl-tile-handler-log.h	\
     gegl-tile-handler-zoom.h
 
+libbuffer_la_LIBADD = -lm