From: "Martin Bickel"
Subject: [SDL] Patch: fixing uninitilized palette

while running Valgrind over my application I found the following
problem in SDL:

The function MapNto1 allocates  SDL_Color colors[256]  but does not
initialize it.
SDL_DitherColors is then called which initialized the r, g and b
component, but not the 'unused' component of each color.
When Map1to1 is called from MapNto1, it runs a memcmp on the colors,
which also evaluates the unused component and therefor returns
differences much more often than necessary.

So the 'unused' component of SDL_Color should be initialized. This
patch does this by calling memset for the whole array in MapNto1 .

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40998