Merge pull request #4333 from mysterywolf/pthread

[pthread][libc][time] 修改pthread与libc的时间函数若干问题

components/libc/compilers/armlibc/libc_syms.c

@@ -10,8 +10,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
-#include <time.h>
-
 #include <rtm.h>
 
 /* some export routines for module */
@@ -35,11 +33,6 @@ RTM_EXPORT(memchr);
 RTM_EXPORT(toupper);
 RTM_EXPORT(atoi);
 
-#ifdef RT_USING_RTC
-RTM_EXPORT(localtime);
-RTM_EXPORT(time);
-#endif
-
 /* import the full stdio for printf */
 #if defined(RT_USING_MODULE) && defined(__MICROLIB)
 #error "[RT_USING_LIBC] Please use standard libc but not microlib."