CCFLAGS is used by gcc and g++ compiler. So CFLAGS should be used for gcc to avoid passing gcc flags to g++.
1. Add NUC980 Chili board supporting. 2. Correct NuMicro.h including. 3. Implement rt_hw_us_delay system call function. 4. Move board.c to drv_common.c for M480 and M2354 series.