Compilation using GCC

When using GCC to compile SDL are there any special things to look out
for? Like type sizes or similar?

I have compiled the SDL Aliens demo and when it runs it does not erase
the object correctly, so the player does not appear to move and the
aliens leave an image trail, though sound/music and collision detection
work fine. When the same source is compiled with Visual C++ all is well
and runs fine, not anomolies.

Can anyone shed some light on what could be going wrong here?


Dominique := go on, write a game instead;