[ucsim] Apply mingw-w64-sdcc/0001-Resolved-conflict-between-define-B-and-system-header.patch
[ucsim] Small doc fixes
[ucsim-s51] Fix call of sfr operators by bit ops
Use simif to stop the simulation as in other ports
Apply patch #497 by Oleg Endo to emit __sdcc_program_exit label
[ucsim] Intro -m option to return main() value
[ucsim-s51] Turn off feature by #497 as it breaks regtests
[ucsim] Apply v2 of #497