forbid invalid comparison of struct
forbid invalid comparison of struct

Current tcc permits comparison of structs and comparison between
struct and other typed values.

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