[Xvid-devel] Small win32 updates

[Elio Blanca]

This patch updates the Makefile for example utilities, making it able to change needed linker 
libraries depending upon the detected environment (win32 or not).
Further, xvid_encraw.c was slightly modified. Actually it can be built with AVI file support both 
for input and output but enabling just one (and not the other) makes gcc complain. This won't happen 
anymore and AVI file support can be enabled just for input or just for output.
Elio