I added mouse wheel weapon change to prboom
the prevweapon and nextweapon keys can be assigned to
any keys or the mouse wheel up/down functions.
Just copy the wheelweapons.patch file to your
prboom-2.3.0/src directory and from that directory
patch -p0 <wheelweapons.patch
Then from the prboom-2.3.0 directory do:
go into the options key assignments weapons keys menu
and set up your keys or mouse wheel functions to assign
to the prev weapon and next weapon functions.