gcov: fix link undefined error

undefined reference to `__gcov_execle'

Signed-off-by: buxiasen <buxiasen@xiaomi.com>

libs/libbuiltin/libgcc/gcov.c

@@ -464,6 +464,10 @@ void __gcov_execv(void)
 {
 }
 
+void __gcov_execle(void)
+{
+}
+
 pid_t __gcov_fork(void)
 {
   return fork();