Fixed compilation of amuled with wx 2.9.5

Using internal undocumented wx stuff finally caught up.
So the "prevent child zombie processes" code had to be disabled for wx 2.9.5 and later.
No idea if that was important or just somebodies attempt to show off.
amuled appears to work just fine still.

:: upstream revision 10807 ::
Fixed compilation of amuled with wx 2.8 (broken in last change)

:: upstream revision 10808 ::