Sets KOKKOS_ENABLE_EXPLICIT_INSTANTIATION=OFF by default

Explicit type instantiation for fill/copy will have to be evaluated. Deactivated
by now since it is heavy compilation time consuming in a small project as pastis ATM

CMakeLists.txt

@@ -82,6 +82,9 @@ if(${OPENMP_FOUND})
   set(KOKKOS_ENABLE_OPENMP ON CACHE BOOL "")
 endif()
 
+# do not build ETI by default
+set(KOKKOS_ENABLE_EXPLICIT_INSTANTIATION OFF CACHE BOOL "")
+
 # Kokkso compiler flags
 add_subdirectory(${PASTIS_SOURCE_DIR}/packages/kokkos)
 include_directories(${Kokkos_INCLUDE_DIRS_RET})