add missing c++ extern "C" wrapping to link.h

include/link.h

@@ -1,6 +1,10 @@
 #ifndef _LINK_H
 #define _LINK_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <elf.h>
 #define __NEED_size_t
 #define __NEED_uint32_t
@@ -43,4 +47,8 @@ struct r_debug {
 
 int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *), void *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif