use glPixelStorei to set GL_PACK_SWAP_BYTES to GL_FALSE
draw a group of values into stencil buffer, 
then, use glPixelStorei to set GL_PACK_SWAP_BYTES to GL_TRUE
read back values from buffer, the byte order is not as expected.

The following patch should fix this:

--- src/mesa/main/image.c       2007-08-05 20:06:34.000000000 +0800
+++ src/mesa/main/b.c   2007-08-09 13:23:01.000000000 +0800
@@ -3794,7 +3794,7 @@
          GLint *dst = (GLint *) dest;
          GLuint i;
          for (i=0;i<n;i++) {
-            *dst++ = (GLint) source[i];
+            dst[i] = (GLint) source[i];
          }
          if (dstPacking->SwapBytes) {
             _mesa_swap4( (GLuint *) dst, n );