common.make -- debug=yes

[Giah de Barag]

Would you review these two lines intended for insertion at common.make:756 . . .

ifeq ($(debug), yes)

  # Optimization flags are filtered out as they make debugging harder.

  OPTFLAG := $(filter-out -O%, $(OPTFLAG))

  CCFLAGS := $(filter-out -O%, $(CCFLAGS))

  ADDITIONAL_FLAGS := $(filter-out -O%, $(ADDITIONAL_FLAGS))

  # If OPTFLAG does not already include -g, add it here.

  ifneq ($(filter -g, $(OPTFLAG)), -g)

    ADDITIONAL_FLAGS += -g

  endif

. . . without which debug=yes does not get rid of the -O2 flag.