Add extern c around jpeg header

BUG=305
TESTED=try bots
R=michaelbai@chromium.org

Review URL: https://webrtc-codereview.appspot.com/7069004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@967 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 966
+Version: 967
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 966
+#define LIBYUV_VERSION 967
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/mjpeg_decoder.cc

@@ -18,8 +18,18 @@
 #define HAVE_SETJMP
 #endif
 struct FILE;  // For jpeglib.h.
+
+// C++ build requires extern C for jpeg internals.
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <jpeglib.h>
 
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
 #include "libyuv/planar_functions.h"  // For CopyPlane().
 
 namespace libyuv {