Fix compiler warning for gcc 4.4.3

c_src/decoder.c

@@ -16,7 +16,7 @@
 #define STACK_SIZE_INC 64
 #define NUM_BUF_LEN 32
 
-#ifdef WINDOWS || WIN32
+#if WINDOWS || WIN32
 #define snprintf  _snprintf
 #endif
 

c_src/encoder.c

@@ -20,7 +20,7 @@ do {                                \
     }                               \
 } while(0)
 
-#ifdef WINDOWS || WIN32
+#if WINDOWS || WIN32
 #define inline __inline
 #define snprintf  _snprintf
 #endif