Upstream issue 223, http://code.google.com/p/openjpeg/issues/detail?id=223

--- openjpeg-2.0.0/src/lib/openjp2/libopenjp2.pc.cmake.in
+++ openjpeg-2.0.0/src/lib/openjp2/libopenjp2.pc.cmake.in
@@ -10,4 +10,5 @@
 URL: http://www.openjpeg.org/
 Version: @OPENJPEG_VERSION@
 Libs: -L${libdir} -lopenjp2
+Libs.private: -L${libdir} -lopenjp2 -lm
 Cflags: -I${includedir}