link: Use linkat if arch does not have the link syscall

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

include/unistd.h

@@ -887,6 +887,7 @@ extern int link (const char *__from, const char *__to)
 extern int linkat (int __fromfd, const char *__from, int __tofd,
 		   const char *__to, int __flags)
      __THROW __nonnull ((2, 4)) __wur;
+libc_hidden_proto(linkat)
 #endif
 
 #if defined __USE_BSD || defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K

libc/sysdeps/linux/common/link.c

@@ -9,4 +9,13 @@
 
 #include <sys/syscall.h>
 #include <unistd.h>
+
+#if defined __NR_linkat && !defined __NR_link
+# include <fcntl.h>
+int link(const char *oldpath, const char *newpath)
+{
+	return linkat(AT_FDCWD, oldpath, AT_FDCWD, newpath, 0);
+}
+#else
 _syscall2(int, link, const char *, oldpath, const char *, newpath)
+#endif

libc/sysdeps/linux/common/linkat.c

@@ -11,6 +11,7 @@
 
 #ifdef __NR_linkat
 _syscall5(int, linkat, int, fromfd, const char *, from, int, tofd, const char *, to, int, flags)
+libc_hidden_def(linkat)
 #else
 /* should add emulation with link() and /proc/self/fd/ ... */
 #endif