Add necessary header file.

git-svn-id: https://svn.dealii.org/trunk@24400 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/distributed/tria.h b/deal.II/include/deal.II/distributed/tria.h
index 62d91ad0c6945fbaa142b74e1c9b232604f27b15..1d98cd845a71981ba4fc95e0a445270689984dec 100644 (file)
--- a/deal.II/include/deal.II/distributed/tria.h
+++ b/deal.II/include/deal.II/distributed/tria.h
@@ -25,6 +25,10 @@
 #include <list>
 #include <utility>
 
+#ifdef DEAL_II_COMPILER_SUPPORTS_MPI
+#  include <mpi.h>
+#endif
+
 #ifdef DEAL_II_USE_P4EST
 #include <p4est_connectivity.h>
 #include <p4est.h>