[newlib-cygwin] Avoid crash when calling __localeconv_l with __C_locale

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a703d64ad7edac344e4959e8d624ce1d8012678b

commit a703d64ad7edac344e4959e8d624ce1d8012678b
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Wed Aug 24 19:46:55 2016 +0200

    Avoid crash when calling __localeconv_l with __C_locale
    
    __C_locale is const.  Thus, overwriting the lconv values in __localeconv_l
    will try to write to a R/O region.  Given the lconv values in __C_locale
    are initialized, there's no reason to write them in __localeconv_l at all.
    Just return &__C_locale.lconv.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 newlib/libc/locale/localeconv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/newlib/libc/locale/localeconv.c b/newlib/libc/locale/localeconv.c
index 1f8816d..165f6f7 100644
--- a/newlib/libc/locale/localeconv.c
+++ b/newlib/libc/locale/localeconv.c
@@ -6,6 +6,9 @@ struct lconv *
 __localeconv_l (struct __locale_t *locale)
 {
   struct lconv *lconv = &locale->lconv;
+  if (locale == __get_C_locale ())
+    return lconv;
+
 #ifdef __HAVE_LOCALE_INFO__
   const struct lc_numeric_T *n = __get_numeric_locale (locale);
   const struct lc_monetary_T *m = __get_monetary_locale (locale);