Re-submit "Name function arguments in libc headers for Studio."

This reverts commit 9af9120091ceb96641d7c6c645fabad96db4bc0d (a revert
of 079bff4fa52b0c3c76057451cc9cdecf1827fce0), now the versioner bug is
fixed.

Bug: http://b/64613623 # header bug
Bug: http://b/64802958 # versioner bug
Change-Id: I1cb9d7832d4b3aecdc57a9285e2291443e59d02d
diff --git a/libc/include/link.h b/libc/include/link.h
index dd3b99f..072f093 100644
--- a/libc/include/link.h
+++ b/libc/include/link.h
@@ -50,9 +50,9 @@
 };
 
 #if defined(__arm__)
-int dl_iterate_phdr(int (*)(struct dl_phdr_info*, size_t, void*), void*) __INTRODUCED_IN(21);
+int dl_iterate_phdr(int (*__callback)(struct dl_phdr_info*, size_t, void*), void* __data) __INTRODUCED_IN(21);
 #else
-int dl_iterate_phdr(int (*)(struct dl_phdr_info*, size_t, void*), void*);
+int dl_iterate_phdr(int (*__callback)(struct dl_phdr_info*, size_t, void*), void* __data);
 #endif
 
 #ifdef __arm__
@@ -84,4 +84,4 @@
 
 __END_DECLS
 
-#endif /* _LINK_H_ */
+#endif