fix constant optimization for unsigneds
fix constant optimization for unsigneds

acook/tinycc,mirror/tinycc,rchandramouli/tinycc,alfonsokim/tinycc,mingodad/tinycc,code4game/tinycc,shinh/nacltcc,andrewchambers/tccmirror,run4flat/tinycc,melkior/tinycc,acook/tinycc,run4flat/tinycc,Wallbraker/DCPU-TCC,run4flat/tinycc,melkior/tinycc,fstudio/tinycc,mingodad/tinycc,fstudio/tinycc,avih/tinycc,FriedBreakfast/tcc,seyko2/tinycc,fstudio/tinycc,mobiphil/tinnycc,mirror/tinycc,seyko2/tinycc,alfonsokim/tinycc,rchandramouli/tinycc,leeduhem/tinycc,gfwilliams/tinycc,Saectar/inherpreter,leeduhem/tinycc,ftdi-paul-jiao/tinyCC,yousong/tinycc,metaeducation/tcc,ftdi-paul-jiao/tinyCC,Wallbraker/DCPU-TCC,code4game/tinycc,alfonsokim/tinycc,fstudio/tinycc,avih/tinycc,metaeducation/tcc,andreiw/tinycc,gfwilliams/tinycc,mobiphil/tinnycc,Wallbraker/DCPU-TCC,rchandramouli/tinycc,seyko2/tinycc,shinh/nacltcc,alfonsokim/tinycc,acook/tinycc,seyko2/tinycc,Saectar/inherpreter,ftdi-paul-jiao/tinyCC,gfwilliams/tinycc,andreiw/tinycc,xcm/tcc,soywiz/tinycc,gfwilliams/tinycc,acook/tinycc,seyko2/tinycc,Archs/TinyCC,soywiz/tinycc,ftdi-paul-jiao/tinyCC,leeduhem/tinycc,FriedBreakfast/tcc,Saectar/inherpreter,andrewchambers/tccmirror,Archs/TinyCC,mitake/tinycc,mirror/tinycc,andreiw/tinycc,metaeducation/tcc,leeduhem/tinycc,metaeducation/tcc,Archs/TinyCC,leeduhem/tinycc,mirror/tinycc,FriedBreakfast/tcc,metaeducation/tcc,xcm/tcc,run4flat/tinycc,yousong/tinycc,yousong/tinycc,andrewchambers/tccmirror,gfwilliams/tinycc,soywiz/tinycc,avih/tinycc,Saectar/inherpreter,yousong/tinycc,Archs/TinyCC,shinh/nacltcc,melkior/tinycc,avih/tinycc,mitake/tinycc,mobiphil/tinnycc,Archs/TinyCC,xcm/tcc,shinh/nacltcc,andrewchambers/tccmirror,andrewchambers/tccmirror,rchandramouli/tinycc,Saectar/inherpreter,melkior/tinycc,mitake/tinycc,rchandramouli/tinycc,mitake/tinycc,mobiphil/tinnycc,mingodad/tinycc,code4game/tinycc,FriedBreakfast/tcc,soywiz/tinycc,melkior/tinycc,run4flat/tinycc,mingodad/tinycc,alfonsokim/tinycc,shinh/nacltcc,FriedBreakfast/tcc,fstudio/tinycc