Refactor: Add C++ guard code to headers

C++ is used more and more, and it is becoming more and more annoying to
keep track of whether header have C++ guard or not.

Is easier and more clear to be consistent in all headers and have such
guards in all headers.

source/blender/blenkernel/BKE_action.h

@@ -25,6 +25,10 @@
  * \brief Blender kernel action and pose functionality.
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "DNA_listBase.h"
 
 /* The following structures are defined in DNA_action_types.h, and DNA_anim_types.h */
@@ -38,11 +42,6 @@ struct bPose;
 struct bPoseChannel;
 struct bPoseChannel_Runtime;
 
-/* Kernel prototypes */
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* Action Lib Stuff ----------------- */
 
 /* Allocate a new bAction with the given name */

source/blender/blenkernel/BKE_animsys.h

@@ -24,6 +24,10 @@
  * \ingroup bke
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct AnimData;
 struct Depsgraph;
 struct FCurve;
@@ -297,4 +301,8 @@ void BKE_animsys_update_driver_array(struct ID *id);
 
 /* ************************************* */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __BKE_ANIMSYS_H__*/

source/blender/blenkernel/BKE_modifier.h

@@ -20,6 +20,10 @@
  * \ingroup bke
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "DNA_modifier_types.h" /* needed for all enum typdefs */
 #include "BLI_compiler_attrs.h"
 #include "BKE_customdata.h"
@@ -461,4 +465,8 @@ void modwrap_deformVertsEM(ModifierData *md,
 struct Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(struct Object *ob_eval,
                                                                    const bool get_cage_mesh);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

source/blender/blenkernel/BKE_sequencer.h

@@ -24,6 +24,10 @@
  * \ingroup bke
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct Depsgraph;
 struct Editing;
 struct GPUOffScreen;
@@ -599,4 +603,8 @@ void BKE_sequencer_color_balance_apply(struct StripColorBalance *cb,
 
 void BKE_sequencer_all_free_anim_ibufs(struct Scene *scene, int cfra);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __BKE_SEQUENCER_H__ */

source/blender/blenkernel/BKE_sound.h

@@ -23,6 +23,10 @@
  * \ingroup bke
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define SOUND_WAVE_SAMPLES_PER_SECOND 250
 
 #if defined(WITH_AUDASPACE)
@@ -190,4 +194,8 @@ struct Depsgraph;
 
 void BKE_sound_evaluate(struct Depsgraph *depsgraph, struct Main *bmain, struct bSound *sound);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __BKE_SOUND_H__ */

source/blender/draw/DRW_engine.h

@@ -23,6 +23,10 @@
 #ifndef __DRW_ENGINE_H__
 #define __DRW_ENGINE_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "BLI_sys_types.h" /* for bool */
 
 struct ARegion;
@@ -166,4 +170,8 @@ void DRW_deferred_shader_remove(struct GPUMaterial *mat);
 struct DrawDataList *DRW_drawdatalist_from_id(struct ID *id);
 void DRW_drawdata_free(struct ID *id);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __DRW_ENGINE_H__ */

source/blender/makesdna/DNA_action_types.h

@@ -28,6 +28,10 @@
 #ifndef __DNA_ACTION_TYPES_H__
 #define __DNA_ACTION_TYPES_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "DNA_listBase.h"
 #include "DNA_ID.h"
 #include "DNA_view2d_types.h"
@@ -955,4 +959,8 @@ typedef enum eActionChannelFlag {
   ACHAN_MOVED = (1u << 31),
 } eActionChannelFlag;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __DNA_ACTION_TYPES_H__ */

source/blender/makesdna/DNA_mesh_types.h

@@ -28,6 +28,10 @@
 #include "DNA_ID.h"
 #include "DNA_customdata_types.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct AnimData;
 struct Ipo;
 struct Key;
@@ -277,4 +281,8 @@ enum {
 
 #define MESH_MAX_VERTS 2000000000L
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

source/blender/makesdna/DNA_movieclip_types.h

@@ -24,6 +24,10 @@
 #ifndef __DNA_MOVIECLIP_TYPES_H__
 #define __DNA_MOVIECLIP_TYPES_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "DNA_ID.h"
 #include "DNA_tracking_types.h"
 #include "DNA_color_types.h" /* for color management */
@@ -207,4 +211,8 @@ enum {
   MCLIP_PROXY_RENDER_USE_FALLBACK_RENDER = 2,
 };
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

source/blender/makesdna/DNA_sequence_types.h

@@ -37,6 +37,10 @@
 #include "DNA_vec_types.h"
 #include "DNA_vfont_types.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct Ipo;
 struct MovieClip;
 struct Scene;
@@ -680,4 +684,8 @@ enum {
   SEQ_CACHE_PREFETCH_ENABLE = (1 << 10),
 };
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __DNA_SEQUENCE_TYPES_H__ */