avcodec/texturedspenc: Add () to protect macro / argument evaluation order

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/texturedspenc.c

@@ -140,14 +140,14 @@ const static uint8_t match6[256][2] = {
 };
 
 /* Multiplication over 8 bit emulation */
-#define mul8(a, b) (a * b + 128 + ((a * b + 128) >> 8)) >> 8
+#define mul8(a, b) (((a) * (b) + 128 + (((a) * (b) + 128) >> 8)) >> 8)
 
 /* Conversion from rgb24 to rgb565 */
 #define rgb2rgb565(r, g, b) \
-    (mul8(r, 31) << 11) | (mul8(g, 63) << 5) | (mul8(b, 31) << 0)
+    ((mul8(r, 31) << 11) | (mul8(g, 63) << 5) | (mul8(b, 31) << 0))
 
 /* Linear interpolation at 1/3 point between a and b */
-#define lerp13(a, b) (2 * a + b) / 3
+#define lerp13(a, b) ((2 * (a) + (b)) / 3)
 
 /* Linear interpolation on an RGB pixel */
 static inline void lerp13rgb(uint8_t *out, uint8_t *p1, uint8_t *p2)