drm: add extern C guard for the UAPI headers

Signed-off-by: Emil Velikov <[e-mail]>

include/uapi/drm/drm.h

···
 
 #endif
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define DRM_NAME	"drm"	  /**< Name in kernel, /dev, and /proc */
 #define DRM_MIN_ORDER	5	  /**< At least 2^5 bytes = 32 bytes */
 #define DRM_MAX_ORDER	22	  /**< Up to 2^22 bytes = 4MB */
···
 	__s32 fd;
 };
 
+#if defined(__cplusplus)
+}
+#endif
+
 #include "drm_mode.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
 
 #define DRM_IOCTL_BASE			'd'
 #define DRM_IO(nr)			_IO(DRM_IOCTL_BASE,nr)
···
 typedef struct drm_agp_info drm_agp_info_t;
 typedef struct drm_scatter_gather drm_scatter_gather_t;
 typedef struct drm_set_version drm_set_version_t;
+#endif
+
+#if defined(__cplusplus)
+}
 #endif
 
 #endif

include/uapi/drm/drm_fourcc.h

···
 
 #include "drm.h"
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define fourcc_code(a, b, c, d) ((__u32)(a) | ((__u32)(b) << 8) | \
 				 ((__u32)(c) << 16) | ((__u32)(d) << 24))
 
···
  * For more information: see https://linuxtv.org/downloads/v4l-dvb-apis/re32.html
  */
 #define DRM_FORMAT_MOD_SAMSUNG_64_32_TILE	fourcc_mod_code(SAMSUNG, 1)
+
+#if defined(__cplusplus)
+}
+#endif
 
 #endif /* DRM_FOURCC_H */

include/uapi/drm/drm_mode.h

···
 
 #include "drm.h"
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 #define DRM_DISPLAY_INFO_LEN	32
 #define DRM_CONNECTOR_NAME_LEN	32
 #define DRM_DISPLAY_MODE_LEN	32
···
 struct drm_mode_destroy_blob {
 	__u32 blob_id;
 };
+
+#if defined(__cplusplus)
+}
+#endif
 
 #endif

include/uapi/drm/drm_sarea.h

···
 
 #include "drm.h"
 
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
 /* SAREA area needs to be at least a page */
 #if defined(__alpha__)
 #define SAREA_MAX                       0x2000U
···
 typedef struct drm_sarea_drawable drm_sarea_drawable_t;
 typedef struct drm_sarea_frame drm_sarea_frame_t;
 typedef struct drm_sarea drm_sarea_t;
+#endif
+
+#if defined(__cplusplus)
+}
 #endif
 
 #endif				/* _DRM_SAREA_H_ */