i386-gen: use EBX as 4th register
i386-gen: use EBX as 4th register

May be enabled/disabled by changing this line:
    #define USE_EBX 1

mingodad/tinycc,mingodad/tinycc,mirror/tinycc,code4game/tinycc,mingodad/tinycc,andreiw/tinycc,run4flat/tinycc,avih/tinycc,mirror/tinycc,avih/tinycc,run4flat/tinycc,mirror/tinycc,code4game/tinycc,run4flat/tinycc,mingodad/tinycc,andreiw/tinycc,andreiw/tinycc,run4flat/tinycc,avih/tinycc,mirror/tinycc,run4flat/tinycc,avih/tinycc,code4game/tinycc