diff -up avogadro-1.1.1/avogadro.pc.in.eigen avogadro-1.1.1/avogadro.pc.in
--- avogadro-1.1.1/avogadro.pc.in.eigen	2013-12-06 09:50:04.000000000 -0600
+++ avogadro-1.1.1/avogadro.pc.in	2014-01-25 00:37:45.732007852 -0600
@@ -9,3 +9,4 @@ Description: Avogadro libraries
 Version: @Avogadro_VERSION_FULL@
 Libs: -L${libdir} -lavogadro
 Cflags: -I${pkgincludedir}
+Requires.private: eigen2