diff --git a/libswscale/yuv2rgb.c b/libswscale/yuv2rgb.c
index c7b7d4037676db0cd303cf3e7a24716587bb8809..71759bc94e005fd08dd72897e22a45e43789f3e0 100644
--- a/libswscale/yuv2rgb.c
+++ b/libswscale/yuv2rgb.c
@@ -156,26 +156,26 @@ const uint8_t  __attribute__((aligned(8))) dither_8x8_220[8][8]={
 #ifdef HAVE_MMX
 
 /* hope these constant values are cache line aligned */
-uint64_t attribute_used __attribute__((aligned(8))) mmx_00ffw = 0x00ff00ff00ff00ffULL;
-uint64_t attribute_used __attribute__((aligned(8))) mmx_redmask = 0xf8f8f8f8f8f8f8f8ULL;
-uint64_t attribute_used __attribute__((aligned(8))) mmx_grnmask = 0xfcfcfcfcfcfcfcfcULL;
+static uint64_t attribute_used __attribute__((aligned(8))) mmx_00ffw = 0x00ff00ff00ff00ffULL;
+static uint64_t attribute_used __attribute__((aligned(8))) mmx_redmask = 0xf8f8f8f8f8f8f8f8ULL;
+static uint64_t attribute_used __attribute__((aligned(8))) mmx_grnmask = 0xfcfcfcfcfcfcfcfcULL;
 
-uint64_t attribute_used __attribute__((aligned(8))) M24A=   0x00FF0000FF0000FFULL;
-uint64_t attribute_used __attribute__((aligned(8))) M24B=   0xFF0000FF0000FF00ULL;
-uint64_t attribute_used __attribute__((aligned(8))) M24C=   0x0000FF0000FF0000ULL;
+static uint64_t attribute_used __attribute__((aligned(8))) M24A=   0x00FF0000FF0000FFULL;
+static uint64_t attribute_used __attribute__((aligned(8))) M24B=   0xFF0000FF0000FF00ULL;
+static uint64_t attribute_used __attribute__((aligned(8))) M24C=   0x0000FF0000FF0000ULL;
 
 // the volatile is required because gcc otherwise optimizes some writes away not knowing that these
 // are read in the asm block
-volatile uint64_t attribute_used __attribute__((aligned(8))) b5Dither;
-volatile uint64_t attribute_used __attribute__((aligned(8))) g5Dither;
-volatile uint64_t attribute_used __attribute__((aligned(8))) g6Dither;
-volatile uint64_t attribute_used __attribute__((aligned(8))) r5Dither;
+static volatile uint64_t attribute_used __attribute__((aligned(8))) b5Dither;
+static volatile uint64_t attribute_used __attribute__((aligned(8))) g5Dither;
+static volatile uint64_t attribute_used __attribute__((aligned(8))) g6Dither;
+static volatile uint64_t attribute_used __attribute__((aligned(8))) r5Dither;
 
-uint64_t __attribute__((aligned(8))) dither4[2]={
+static uint64_t __attribute__((aligned(8))) dither4[2]={
 	0x0103010301030103LL,
 	0x0200020002000200LL,};
 
-uint64_t __attribute__((aligned(8))) dither8[2]={
+static uint64_t __attribute__((aligned(8))) dither8[2]={
 	0x0602060206020602LL,
 	0x0004000400040004LL,};