消除编译时隐式声明导致的WARNING信息

components/drivers/rtc/rtc.c

@@ -17,6 +17,7 @@
 
 #include <time.h>
 #include <string.h>
+#include <stdlib.h>
 
 /* Using NTP auto sync RTC time */
 #ifdef RTC_SYNC_USING_NTP

libcpu/aarch64/common/mmu.h

@@ -135,4 +135,6 @@ void *rt_hw_mmu_v2p(rt_mmu_info *mmu_info, void* v_addr);
 void rt_mm_lock(void);
 void rt_mm_unlock(void);
 
+void kernel_mmu_switch(unsigned long tbl);
+
 #endif