diff --git a/eigen3.spec b/eigen3.spec
index 58cc3f7..9864a10 100644
--- a/eigen3.spec
+++ b/eigen3.spec
@@ -1,6 +1,6 @@
 Name:          eigen3
 Version:       3.2.7
-Release:       2mamba
+Release:       3mamba
 Summary:       A C++ template library for linear algebra
 Group:         System/Libraries
 Vendor:        openmamba
@@ -34,7 +34,9 @@ mv eigen-* eigen
 
 %build
 cd eigen
-%cmake -d build
+%cmake -d build \
+   -DINCLUDE_INSTALL_DIR=%{_includedir}/eigen3
+
 %make
 cd ..
 make doc
@@ -54,6 +56,9 @@ cd eigen
 %doc eigen/COPYING.*
 
 %changelog
+* Fri Jan 01 2016 Silvan Calarco <silvan.calarco@mambasoft.it> 3.2.7-3mamba
+- really fix pkgconfig file
+
 * Wed Dec 23 2015 Silvan Calarco <silvan.calarco@mambasoft.it> 3.2.7-2mamba
 - fix pkgconfig include dir