[PULL] button mapping fix and unconstify patches

[Gaetan Nadon]

On 14-02-11 12:08 AM, Keith Packard wrote:
> It's not just the GCC version, unfortunately. I have a pile of versions,
> and cannot generate any of the (useful) warnings that you have managed
> to elicit from the compiler.
I tried Ubuntu 13-10 with gcc 4.8.2.  The 32-bit version

  35 -Wunused-result
   0 -Wpointer-arith    (as expected)
   0 -Wformat		(you have 1)
   1 -Wunused-function

On the 64 bit with gcc 4.6.3:

  35 -Wunused-result
   2 -Wpointer-arith
   2 -Wformat
   1 -Wunused-function