[PATCH] Fix few build warnings with LLVM toolchain

[David CARLIER]

Hi,

Here a tiny patch to fix few build warnings.

Kind regards.

Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog	(revision 271684)
+++ gcc/ChangeLog	(working copy)
@@ -1,3 +1,7 @@
+2019-05-28  David Carlier <devne...@gmail.com>
+
+        * coretypes.h: Fix build warning, chaing few classes to struct.
+
 2019-05-27  Jakub Jelinek  <ja...@redhat.com>
 
 	* gimplify.c (gimplify_scan_omp_clauses): Allow lastprivate conditional
Index: gcc/coretypes.h
===================================================================
--- gcc/coretypes.h	(revision 271684)
+++ gcc/coretypes.h	(working copy)
@@ -65,7 +65,7 @@ template<typename> class opt_mode;
 typedef opt_mode<scalar_mode> opt_scalar_mode;
 typedef opt_mode<scalar_int_mode> opt_scalar_int_mode;
 typedef opt_mode<scalar_float_mode> opt_scalar_float_mode;
-template<typename> class pod_mode;
+template<typename> struct pod_mode;
 typedef pod_mode<scalar_mode> scalar_mode_pod;
 typedef pod_mode<scalar_int_mode> scalar_int_mode_pod;
 typedef pod_mode<fixed_size_mode> fixed_size_mode_pod;
@@ -73,7 +73,7 @@ typedef pod_mode<fixed_size_mode> fixed_
 /* Subclasses of rtx_def, using indentation to show the class
    hierarchy, along with the relevant invariant.
    Where possible, keep this list in the same order as in rtl.def.  */
-class rtx_def;
+struct rtx_def;
   class rtx_expr_list;           /* GET_CODE (X) == EXPR_LIST */
   class rtx_insn_list;           /* GET_CODE (X) == INSN_LIST */
   class rtx_sequence;            /* GET_CODE (X) == SEQUENCE */
@@ -138,7 +138,7 @@ struct gomp_teams;
 /* Subclasses of symtab_node, using indentation to show the class
    hierarchy.  */
 
-class symtab_node;
+struct symtab_node;
   struct cgraph_node;
   class varpool_node;
 
Index: gcc/hash-table.h
===================================================================
--- gcc/hash-table.h	(revision 271684)
+++ gcc/hash-table.h	(working copy)
@@ -347,7 +347,7 @@ hash_table_mod2 (hashval_t hash, unsigne
   return 1 + mul_mod (hash, p->prime - 2, p->inv_m2, p->shift);
 }
 
-class mem_usage;
+struct mem_usage;
 
 /* User-facing hash table type.