Name function arguments in libc headers for Studio.

Second batch of headers...

Bug: http://b/64613623
Test: builds
Change-Id: I8eef043dbf32afee8ff814e9d005f46aee8fa21f
diff --git a/libc/include/locale.h b/libc/include/locale.h
index c1b6299..4290992 100644
--- a/libc/include/locale.h
+++ b/libc/include/locale.h
@@ -98,14 +98,14 @@
 
 struct lconv* localeconv(void) __INTRODUCED_IN(21) __VERSIONER_NO_GUARD;
 
-locale_t duplocale(locale_t) __INTRODUCED_IN(21);
-void freelocale(locale_t) __INTRODUCED_IN(21);
-locale_t newlocale(int, const char*, locale_t) __INTRODUCED_IN(21);
-char* setlocale(int, const char*);
-locale_t uselocale(locale_t) __INTRODUCED_IN(21);
+locale_t duplocale(locale_t __l) __INTRODUCED_IN(21);
+void freelocale(locale_t __l) __INTRODUCED_IN(21);
+locale_t newlocale(int __category_mask, const char* __locale_name, locale_t __base) __INTRODUCED_IN(21);
+char* setlocale(int __category, const char* __locale_name);
+locale_t uselocale(locale_t __l) __INTRODUCED_IN(21);
 
 #define LC_GLOBAL_LOCALE __BIONIC_CAST(reinterpret_cast, locale_t, -1L)
 
 __END_DECLS
 
-#endif /* _LOCALE_H_ */
+#endif