From f22a9edaf8a6f2ca1d314d18b3785558279a5c03 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Tue, 16 Jun 2015 06:18:00 +0000
Subject: [PATCH] byte-based C locale, phase 3: make MB_CUR_MAX variable to
 activate code

this patch activates the new byte-based C locale (high bytes treated
as abstract code unit "characters" rather than decoded as multibyte
characters) by making the value of MB_CUR_MAX depend on the active
locale. for the C locale, the LC_CTYPE category pointer is null,
yielding a value of 1. all other locales yield a value of 4.
---
 include/stdlib.h           | 3 ++-
 src/internal/locale_impl.h | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/stdlib.h b/include/stdlib.h
index 97ce5a72..d2c911fc 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -76,7 +76,8 @@ size_t wcstombs (char *__restrict, const wchar_t *__restrict, size_t);
 #define EXIT_FAILURE 1
 #define EXIT_SUCCESS 0
 
-#define MB_CUR_MAX ((size_t)+4)
+size_t __ctype_get_mb_cur_max(void);
+#define MB_CUR_MAX (__ctype_get_mb_cur_max())
 
 #define RAND_MAX (0x7fffffff)
 
diff --git a/src/internal/locale_impl.h b/src/internal/locale_impl.h
index 85db7933..f5e4d9b4 100644
--- a/src/internal/locale_impl.h
+++ b/src/internal/locale_impl.h
@@ -34,4 +34,7 @@ const char *__lctrans_cur(const char *);
 
 #define CURRENT_UTF8 (!!__pthread_self()->locale->cat[LC_CTYPE])
 
+#undef MB_CUR_MAX
+#define MB_CUR_MAX (CURRENT_UTF8 ? 4 : 1)
+
 #endif