:feat: support link/linkat/symlink/symlinkat/readlink/readlinkat

close #I3Q0OD

Change-Id: I54f538e265619690889c424488993f1aefaa27ee
Signed-off-by: Nchenjing <chenjing139@huawei.com>

src/dirent/dirfd.c

 #include <dirent.h>
 #include "__dirent.h"
-#include <unsupported_api.h>
 
 int dirfd(DIR *d)
 {
-	unsupported_api(__FUNCTION__);
 	return d->fd;
 }

src/unistd/link.c

 #include <unistd.h>
 #include <fcntl.h>
 #include "syscall.h"
-#include <unsupported_api.h>
 
 int link(const char *existing, const char *new)
 {
-	unsupported_api(__FUNCTION__);
 #ifdef SYS_link
 	return syscall(SYS_link, existing, new);
 #else

src/unistd/linkat.c

 #include <unistd.h>
 #include "syscall.h"
-#include <unsupported_api.h>
 
 int linkat(int fd1, const char *existing, int fd2, const char *new, int flag)
 {
-	unsupported_api(__FUNCTION__);
 	return syscall(SYS_linkat, fd1, existing, fd2, new, flag);
 }

src/unistd/readlink.c

-#include <unsupported_api.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include "syscall.h"
 
 ssize_t readlink(const char *restrict path, char *restrict buf, size_t bufsize)
 {
-	unsupported_api(__FUNCTION__);
 #ifdef SYS_readlink
 	return syscall(SYS_readlink, path, buf, bufsize);
 #else

src/unistd/symlink.c

 #include <unistd.h>
 #include <fcntl.h>
-#include <unsupported_api.h>
 
 #include "syscall.h"
 
 int symlink(const char *existing, const char *new)
 {
-	unsupported_api(__FUNCTION__);
 #ifdef SYS_symlink
 	return syscall(SYS_symlink, existing, new);
 #else

src/unistd/symlinkat.c

 #include <unistd.h>
-#include <unsupported_api.h>
 
 #include "syscall.h"
 
 int symlinkat(const char *existing, int fd, const char *new)
 {
-	unsupported_api(__FUNCTION__);
 	return syscall(SYS_symlinkat, existing, fd, new);
 }