libroot/locale: Minor fixes and expose internal POSIX locale.

* We can return early from duplocale() so set the "magic" flag early.
 * Initialize all fields up front.
 * Add an internal method __posix_locale_t() which returns a locale_t
   usable as a global C/POSIX locale type, and add the appropriate
   definition to the musl internal header.

src/system/libroot/posix/locale/locale_t.cpp

@@ -34,14 +34,15 @@ duplocale(locale_t l)
 		errno = ENOMEM;
 		return (locale_t)0;
 	}
+	newObj->magic = LOCALE_T_MAGIC;
+	newObj->backend = NULL;
+	newObj->databridge = NULL;
 
 	LocaleBackend* backend = (l == LC_GLOBAL_LOCALE) ?
 		gGlobalLocaleBackend : (LocaleBackend*)locObj->backend;
 
-	if (backend == NULL) {
+	if (backend == NULL)
-		newObj->backend = NULL;
 		return (locale_t)newObj;
-	}
 
 	// Check if everything is set to "C" or "POSIX",
 	// and avoid making a backend.
@@ -49,7 +50,6 @@ duplocale(locale_t l)
 
 	if ((strcasecmp(localeDescription, "POSIX") == 0)
 			|| (strcasecmp(localeDescription, "C") == 0)) {
-		newObj->backend = NULL;
 		return (locale_t)newObj;
 	}
 
@@ -81,8 +81,6 @@ duplocale(locale_t l)
 		newBackend->SetLocale(lc, backend->SetLocale(lc, NULL));
 	}
 
-	newObj->magic = LOCALE_T_MAGIC;
-
 	return (locale_t)newObj;
 }
 
@@ -275,3 +273,13 @@ __current_locale_t()
 
 	return locale;
 }
+
+
+extern "C" locale_t
+__posix_locale_t()
+{
+	static LocaleBackendData posix_locale_t;
+	posix_locale_t.backend = NULL;
+	posix_locale_t.databridge = NULL;
+	return &posix_locale_t;
+}

src/system/libroot/posix/musl/internal/locale_impl.h

@@ -10,6 +10,8 @@
 #define __nl_langinfo_l nl_langinfo_l
 
 locale_t __current_locale_t();
+locale_t __posix_locale_t();
 #define CURRENT_LOCALE (__current_locale_t())
+#define C_LOCALE (__posix_locale_t())
 
 #endif