Index: eigen-3.3.8/cmake/FindGoogleHash.cmake
===================================================================
--- eigen-3.3.8.orig/cmake/FindGoogleHash.cmake
+++ eigen-3.3.8/cmake/FindGoogleHash.cmake
@@ -12,6 +12,8 @@ find_path(GOOGLEHASH_INCLUDES
 
 if(GOOGLEHASH_INCLUDES)
   # let's make sure it compiles with the current compiler
+  # C++11 is needed for googlehash
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
   file(WRITE ${CMAKE_BINARY_DIR}/googlehash_test.cpp
   "#include <google/sparse_hash_map>\n#include <google/dense_hash_map>\nint main(int argc, char** argv) { google::dense_hash_map<int,float> a; google::sparse_hash_map<int,float> b; return 0;}\n")
   try_compile(GOOGLEHASH_COMPILE ${CMAKE_BINARY_DIR} ${CMAKE_BINARY_DIR}/googlehash_test.cpp OUTPUT_VARIABLE GOOGLEHASH_COMPILE_RESULT)