swig: ifdef some Java specific code

no implementation change

Change-Id: I077c707e1f6293188e6fa11ba24757009a709f77
diff --git a/swig/libwebp.i b/swig/libwebp.i
index b2014e1..de80b6e 100644
--- a/swig/libwebp.i
+++ b/swig/libwebp.i
@@ -71,7 +71,10 @@
 %{
 #include "webp/decode.h"
 #include "webp/encode.h"
+%}
 
+#ifdef SWIGJAVA
+%{
 #define FillMeInAsSizeCannotBeDeterminedAutomatically \
     (result ? returned_buffer_size(__FUNCTION__, arg3, arg4) : 0)
 
@@ -108,6 +111,10 @@
 
   return size;
 }
+%}
+#endif  /* SWIGJAVA */
+
+%{
 
 typedef size_t (*WebPEncodeFunction)(const uint8_t* rgb,
                                      int width, int height, int stride,