python: Use explicit integer divisions

In Python 2, divisions of integers return an integer:

    >>> 32 / 4
    8

In Python 3 though, they return floats:

    >>> 32 / 4
    8.0

However, Python 3 has an explicit integer division operator:

    >>> 32 // 4
    8

That operator exists on Python >= 2.2, so let's use it everywhere to
make the scripts compatible with both Python 2 and 3.

In addition, using __future__.division tells Python 2 to behave the same
way as Python 3, which helps ensure the scripts produce the same output
in both versions of Python.

Signed-off-by: Mathieu Bridon <bochecha@daitauha.fr>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com> (v2)
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

src/mapi/glapi/gen/glX_proto_send.py

@@ -26,7 +26,7 @@
 #    Ian Romanick <idr@us.ibm.com>
 #    Jeremy Kolb <jkolb@brandeis.edu>
 
-from __future__ import print_function
+from __future__ import division, print_function
 
 import argparse
 
@@ -809,7 +809,7 @@ generic_%u_byte( GLint rop, const void * ptr )
                     # Dividing by the array size (1 for
                     # non-arrays) gives us this.
 
-                    s = p.size() / p.get_element_count()
+                    s = p.size() // p.get_element_count()
                     print("       %s __glXReadReply(dpy, %s, %s, %s);" % (return_str, s, p.name, aa))
                     got_reply = 1