vpx: add extern "C" to headers

Change-Id: Ide9a68466ed30453872465a6c2f9c414690df876

vpx/internal/vpx_codec_internal.h

diff --git a/vpx/internal/vpx_codec_internal.h b/vpx/internal/vpx_codec_internal.h
index 6c644f0..9f9da5c 100644
--- a/vpx/internal/vpx_codec_internal.h
+++ b/vpx/internal/vpx_codec_internal.h
@@ -47,6 +47,9 @@
 #include "../vpx_encoder.h"
 #include <stdarg.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /*!\brief Current ABI version number
  *
@@ -476,6 +479,7 @@
 
 #include <stdio.h>
 #include <setjmp.h>
+
 struct vpx_internal_error_info {
   vpx_codec_err_t  error_code;
   int              has_detail;
@@ -532,4 +536,8 @@
                                    const vpx_codec_mmap_t *mmaps,
                                    const mem_req_t *mem_reqs, int nreqs,
                                    vpx_codec_flags_t init_flags);
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
 #endif  // VPX_INTERNAL_VPX_CODEC_INTERNAL_H_

vpx/vpx_image.h

diff --git a/vpx/vpx_image.h b/vpx/vpx_image.h
index 79e11aa..d27325c 100644
--- a/vpx/vpx_image.h
+++ b/vpx/vpx_image.h
@@ -13,13 +13,13 @@
  * \brief Describes the vpx image descriptor and associated operations
  *
  */
+#ifndef VPX_VPX_IMAGE_H_
+#define VPX_VPX_IMAGE_H_
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#ifndef VPX_VPX_IMAGE_H_
-#define VPX_VPX_IMAGE_H_
-
   /*!\brief Current ABI version number
    *
    * \internal
@@ -237,7 +237,8 @@
    */
   void vpx_img_free(vpx_image_t *img);
 
-#endif
 #ifdef __cplusplus
-}
+}  // extern "C"
+#endif
+
 #endif  // VPX_VPX_IMAGE_H_