diff -Nur qgis-1.8.0/cmake/FindSpatialindex.cmake qgis-1.8.0-spatialindex/cmake/FindSpatialindex.cmake
--- qgis-1.8.0/cmake/FindSpatialindex.cmake	2012-03-26 16:47:16.000000000 +0200
+++ qgis-1.8.0-spatialindex/cmake/FindSpatialindex.cmake	2012-04-08 14:04:56.986294861 +0200
@@ -12,7 +12,7 @@
 
 
 FIND_PATH(SPATIALINDEX_INCLUDE_DIR NAMES SpatialIndex.h PATHS
-  /usr/include
+  /usr/include/spatialindex
   /usr/local/include
   "$ENV{LIB_DIR}/include"
   "$ENV{INCLUDE}"