Cleanup: Compile node_draw.c with C++

This will allow using C++ data structures to draw  node error messages.
This required removing a forward declared enum for grease pencil undo.
Compiles with clang tidy.

1 files changed, 9 insertions, 1 deletions

diff --git a/source/blender/editors/space_node/node_intern.h b/source/blender/editors/space_node/node_intern.h
index ee1193af8d0..a7704c5d22c 100644
--- a/source/blender/editors/space_node/node_intern.h
+++ b/source/blender/editors/space_node/node_intern.h
@@ -42,6 +42,10 @@ struct wmGizmoGroupType;
 struct wmKeyConfig;
 struct wmWindow;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* temp data to pass on to modal */
 typedef struct bNodeLinkDrag {
   struct bNodeLinkDrag *next, *prev;
@@ -77,7 +81,7 @@ typedef struct SpaceNode_Runtime {
 /* transform between View2Ds in the tree path */
 void space_node_group_offset(struct SpaceNode *snode, float *x, float *y);
 
-/* node_draw.c */
+/* node_draw.cc */
 float node_socket_calculate_height(const bNodeSocket *socket);
 void node_link_calculate_multi_input_position(const bNodeLink *link, float r[2]);
 
@@ -322,3 +326,7 @@ enum eNodeSpace_ButEvents {
   B_NODE_LOADIMAGE,
   B_NODE_SETIMAGE,
 };
+
+#ifdef __cplusplus
+}
+#endif