Rename LIBC64_HIDDEN to LIBC32_LEGACY_PUBLIC.

Change-Id: If4da9e46398ca5524f6f0680d70588e3dc7e80b4
diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index 58038cd..342cfad 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -432,9 +432,9 @@
 
 /* Like __LIBC_HIDDEN__, but preserves binary compatibility for LP32. */
 #ifdef __LP64__
-#define __LIBC64_HIDDEN__ __LIBC_HIDDEN__
+#define __LIBC32_LEGACY_PUBLIC__ __LIBC_HIDDEN__
 #else
-#define __LIBC64_HIDDEN__ __LIBC_ABI_PUBLIC__
+#define __LIBC32_LEGACY_PUBLIC__ __LIBC_ABI_PUBLIC__
 #endif
 
 /* Used to tag non-static symbols that are public and exposed by the shared library. */