Blenkernel: Move node.c to C++

Required changes to compile `node.cc` with clang tidy:
* Use c++ includes like (e.g. climits instead limits.h).
* Insert type casts when casting from `void *`.
* Replace `NULL` with `nullptr`.
* Replace typedef statements.

This change is in order to use the `blender::Map` data structure
for node error messages.

source/blender/blenkernel/BKE_node.h

@@ -419,7 +419,7 @@ struct GHashIterator *ntreeTypeGetIterator(void);
     GHashIterator *__node_tree_type_iter__ = ntreeTypeGetIterator(); \
     for (; !BLI_ghashIterator_done(__node_tree_type_iter__); \
          BLI_ghashIterator_step(__node_tree_type_iter__)) { \
-      bNodeTreeType *ntype = BLI_ghashIterator_getValue(__node_tree_type_iter__);
+      bNodeTreeType *ntype = (bNodeTreeType *)BLI_ghashIterator_getValue(__node_tree_type_iter__);
 
 #define NODE_TREE_TYPES_END \
   } \
@@ -523,7 +523,7 @@ struct GHashIterator *nodeTypeGetIterator(void);
     GHashIterator *__node_type_iter__ = nodeTypeGetIterator(); \
     for (; !BLI_ghashIterator_done(__node_type_iter__); \
          BLI_ghashIterator_step(__node_type_iter__)) { \
-      bNodeType *ntype = BLI_ghashIterator_getValue(__node_type_iter__);
+      bNodeType *ntype = (bNodeType *)BLI_ghashIterator_getValue(__node_type_iter__);
 
 #define NODE_TYPES_END \
   } \
@@ -545,7 +545,8 @@ const char *nodeStaticSocketInterfaceType(int type, int subtype);
     GHashIterator *__node_socket_type_iter__ = nodeSocketTypeGetIterator(); \
     for (; !BLI_ghashIterator_done(__node_socket_type_iter__); \
          BLI_ghashIterator_step(__node_socket_type_iter__)) { \
-      bNodeSocketType *stype = BLI_ghashIterator_getValue(__node_socket_type_iter__);
+      bNodeSocketType *stype = (bNodeSocketType *)BLI_ghashIterator_getValue( \
+          __node_socket_type_iter__);
 
 #define NODE_SOCKET_TYPES_END \
   } \

source/blender/blenkernel/CMakeLists.txt

@@ -197,7 +197,7 @@ set(SRC
   intern/multires_unsubdivide.c
   intern/multires_versioning.c
   intern/nla.c
-  intern/node.c
+  intern/node.cc
   intern/object.c
   intern/object_deform.c
   intern/object_dupli.c

source/blender/compositor/COM_compositor.h

@@ -298,7 +298,7 @@ extern "C" {
 
 /**
  * \brief The main method that is used to execute the compositor tree.
- * It can be executed during editing (blenkernel/node.c) or rendering
+ * It can be executed during editing (blenkernel/node.cc) or rendering
  * (renderer/pipeline.c)
  *
  * \param rd: [struct RenderData]

source/blender/nodes/texture/node_texture_util.c

@@ -146,7 +146,7 @@ void tex_output(bNode *node,
   }
 
   if (!out->data) {
-    /* Freed in tex_end_exec (node.c) */
+    /* Freed in tex_end_exec (node.cc) */
     dg = out->data = MEM_mallocN(sizeof(TexDelegate), "tex delegate");
   }
   else {