When I use make to compile some code (launch from terminal command line, bash), many (tons) of the sh/make/gcc/automake/autom4te processes become defunct (zombie) afterwards. This doesn't happen when I do it on kde or gnome.

This doesn't happen to all sh/make/gcc processes, but does happen to a lot of them. Very annoying.

As a side note, similar thing happen often to programs launched from Thunar file manager (e.g., double click on a picture/pdf/video file, eog/evince/totem launched), maybe it is because it uses some common library as Terminal program to launch external programs? I filed a bug with Thunar as well.