i915: Avoid aliasing violation.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>

src/mesa/drivers/dri/i915/intel_clear.c

@@ -81,7 +81,7 @@ static void
 intelClear(struct gl_context *ctx, GLbitfield mask)
 {
    struct intel_context *intel = intel_context(ctx);
-   const GLuint colorMask = *((GLuint *) & ctx->Color.ColorMask[0]);
+   GLuint colorMask;
    GLbitfield tri_mask = 0;
    GLbitfield blit_mask = 0;
    GLbitfield swrast_mask = 0;
@@ -89,6 +89,8 @@ intelClear(struct gl_context *ctx, GLbitfield mask)
    struct intel_renderbuffer *irb;
    int i;
 
+   memcpy(&colorMask, &ctx->Color.ColorMask[0], sizeof(colorMask));
+
    if (mask & (BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT)) {
       intel->front_buffer_dirty = true;
    }