OK. Find the answer from the old question. Adding these to the Makefile solves:
ifeq ($(FC),ifort)
FFLAGS += -fpe0 -ftrapuv
CCFLAGS += -O2 -std=c99 -g #added by Elham
endif
I suppose it's better to update the file on the WRF-Chem website, in case anyone meets this issue again in the future.
Best,
Xin