constify a few arrays.

src/glx/x11/pixel.c

@@ -36,7 +36,7 @@
 
 #include "packrender.h"
 
-static GLubyte MsbToLsbTable[256] = {
+static const GLubyte MsbToLsbTable[256] = {
     0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
     0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
     0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
@@ -71,11 +71,11 @@ static GLubyte MsbToLsbTable[256] = {
     0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
 };
 
-static GLubyte LowBitsMask[9] = {
+static const GLubyte LowBitsMask[9] = {
     0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff,
 };
 
-static GLubyte HighBitsMask[9] = {
+static const GLubyte HighBitsMask[9] = {
     0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff,
 };