This basically reverts commit
c4e6460f6 ("MINOR: build: Disable
-Wstringop-overflow.") which is no more needed after previous one.
SPEC_CFLAGS += $(call cc-nowarn,unused-parameter)
SPEC_CFLAGS += $(call cc-nowarn,clobbered)
SPEC_CFLAGS += $(call cc-nowarn,missing-field-initializers)
-SPEC_CFLAGS += $(call cc-nowarn,stringop-overflow)
SPEC_CFLAGS += $(call cc-nowarn,cast-function-type)
SPEC_CFLAGS += $(call cc-nowarn,string-plus-int)
SPEC_CFLAGS += $(call cc-opt,-Wtype-limits)