regex: Gnulib unibyte RRI uses bytes not chars

Adjust the non-glibc code to agree with what Gawk needs for
rational range interpretation (RRI) for regular expression ranges.
In unibyte locales, Gawk wants ranges to use the underlying byte
rather than the character code point.  This change does not affect
glibc proper.
* posix/regcomp.c (parse_byte) [!LIBC && RE_ENABLE_I18N]:
In unibyte locales, use the byte value rather than
running it through btowc.

1 files changed, 4 insertions, 5 deletions

diff --git a/posix/regcomp.c b/posix/regcomp.c
index 3b0a3c6b6a..e81652f229 100644
--- a/posix/regcomp.c
+++ b/posix/regcomp.c
@@ -2684,15 +2684,14 @@ parse_dup_op (bin_tree_t *elem, re_string_t *regexp, re_dfa_t *dfa,
 
 # ifdef RE_ENABLE_I18N
 /* Convert the byte B to the corresponding wide character.  In a
-   unibyte locale, treat B as itself if it is an encoding error.
-   In a multibyte locale, return WEOF if B is an encoding error.  */
+   unibyte locale, treat B as itself.  In a multibyte locale, return
+   WEOF if B is an encoding error.  */
 static wint_t
 parse_byte (unsigned char b, re_charset_t *mbcset)
 {
-  wint_t wc = __btowc (b);
-  return wc == WEOF && !mbcset ? b : wc;
+  return mbcset == NULL ? b : __btowc (b);
 }
-#endif
+# endif
 
   /* Local function for parse_bracket_exp only used in case of NOT _LIBC.
      Build the range expression which starts from START_ELEM, and ends