Implement wctomb(3) for ltrace.

This is an implementation in the style of the rest: char == byte.

We might want to come back and implement UTF-8, but this is enough for ltrace.

Bug: 13747066
Change-Id: Ib2b63609c9014fdef9a8491e067467c4fc5ae3cc
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 9b7e6d1..5dbcb3d 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -151,7 +151,6 @@
 extern const char* getprogname(void);
 extern void setprogname(const char*);
 
-#if 1 /* MISSING FROM BIONIC - ENABLED FOR STLPort and libstdc++-v3 */
 /* make STLPort happy */
 extern int      mblen(const char *, size_t);
 extern size_t   mbstowcs(wchar_t *, const char *, size_t);
@@ -160,7 +159,6 @@
 /* Likewise, make libstdc++-v3 happy.  */
 extern int	wctomb(char *, wchar_t);
 extern size_t	wcstombs(char *, const wchar_t *, size_t);
-#endif /* MISSING */
 
 #define MB_CUR_MAX 1
 
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index 32cf127..89c6fb6 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -36,13 +36,6 @@
 #include <time.h>
 #include <malloc.h>
 
-/* IMPORTANT: Any code that relies on wide character support is essentially
- *            non-portable and/or broken. the only reason this header exist
- *            is because I'm really a nice guy. However, I'm not nice enough
- *            to provide you with a real implementation. instead wchar_t == char
- *            and all wc functions are stubs to their "normal" equivalent...
- */
-
 __BEGIN_DECLS
 
 typedef __WINT_TYPE__           wint_t;
@@ -150,12 +143,11 @@
 extern size_t wcslcat(wchar_t*, const wchar_t*, size_t);
 extern size_t wcslcpy(wchar_t*, const wchar_t*, size_t);
 
-/* No really supported.  These are just for making libstdc++-v3 happy.  */
 typedef void *wctrans_t;
-extern wint_t		 towctrans(wint_t, wctrans_t);
-extern wctrans_t	 wctrans (const char *);
+extern wint_t towctrans(wint_t, wctrans_t);
+extern wctrans_t wctrans(const char*);
 
-#if _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
+#if __POSIX_VISIBLE >= 200809
 wchar_t* wcsdup(const wchar_t*);
 size_t wcsnlen(const wchar_t*, size_t);
 #endif