[glibc] locale: Fix signed char bug in lr_getc

[Florian Weimer <fw@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=19d494445981a09503e4a0175732745c39dd7c21

commit 19d494445981a09503e4a0175732745c39dd7c21
Author: Florian Weimer <fweimer@redhat.com>
Date:   Tue Jul 5 09:05:22 2022 +0200

    locale: Fix signed char bug in lr_getc
    
    The array lr->buf contains characters, which can be signed.  A 0xff
    byte in the input could be incorrectly reported as EOF.  More
    importantly, get_string in linereader.c converts a signed input byte
    to a Unicode code point using ADDWC ((uint32_t) ch), under the
    assumption that this decodes the ISO-8859-1 input encoding.  If char
    is signed, this does not give the correct result.  This means that
    ISO-8859-1 input files for localedef are not actually supported,
    contrary to the comment in get_string.  This is a happy accident because
    we can therefore change the file encoding to UTF-8 without impacting
    backwards compatibility.
    
    While at it, remove the \32 check for MS-DOS end-of-file character (^Z).
    
    Reviewed-by: Carlos O'Donell <carlos@redhat.com>
    Tested-by: Carlos O'Donell <carlos@redhat.com>

Diff:
---
 locale/programs/linereader.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/locale/programs/linereader.h b/locale/programs/linereader.h
index 0fb10ec833..653a71d2d1 100644
--- a/locale/programs/linereader.h
+++ b/locale/programs/linereader.h
@@ -134,7 +134,7 @@ lr_getc (struct linereader *lr)
 	return EOF;
     }
 
-  return lr->buf[lr->idx] == '\32' ? EOF : lr->buf[lr->idx++];
+  return lr->buf[lr->idx++] & 0xff;
 }