Enable UTF8 in gnulib regexp.

* config.h.in (RE_ENABLE_I18N) [!GRUB_UTIL]: New define.
	* grub-core/lib/posix_wrap/ctype.h (islower): Use grub_islower.
	(isupper): Use grub_isupper.
	(isascii): New inline function.
	* grub-core/lib/posix_wrap/wchar.h: Replace dummy with real contents.
	* grub-core/lib/posix_wrap/wctype.h: Likewise.
	* grub-core/normal/charset.c (grub_utf8_process): New function.
	(grub_utf8_to_utf16): Use grub_utf8_process.
	(grub_encode_utf8_character): New function.
	(grub_ucs4_to_utf8): Use grub_encode_utf8_character.
	* include/grub/charset.h (grub_utf8_process): New declaration.
	(grub_encode_utf8_character): Likewise.
	* include/grub/misc.h (grub_islower): New inline function.
	(grub_isupper): Likewise.
	(grub_strchrsub): Moved down to fix the definitions.

grub-core/lib/posix_wrap/wchar.h

@@ -19,7 +19,92 @@
 #ifndef GRUB_POSIX_WCHAR_H
 #define GRUB_POSIX_WCHAR_H	1
 
+#include <grub/charset.h>
+
 /* UCS-4.  */
-typedef grub_uint32_t wchar_t;
+typedef grub_int32_t wint_t;
+enum
+  {
+    WEOF = -1
+  };
+
+#define MB_LEN_MAX 4
+
+/* UCS-4.  */
+typedef grub_int32_t wchar_t;
+
+typedef struct mbstate {
+  grub_uint32_t code;
+  int count;
+} mbstate_t;
+
+static inline size_t
+mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
+{
+  const char *ptr;
+  if (!s)
+    {
+      pwc = 0;
+      s = "";
+      n = 1;
+    }
+
+  for (ptr = s; ptr < s + n; ptr++)
+    {
+      if (!grub_utf8_process (*ptr, &ps->code, &ps->count))
+	return -1;
+      if (ps->count)
+	continue;
+      if (pwc)
+	*pwc = ps->code;
+      if (ps->code == 0)
+	return 0;
+      return ptr - s + 1;
+    }
+  return -2;
+}
+
+static inline int
+mbsinit(const mbstate_t *ps)
+{
+  return ps->count == 0;
+}
+
+static inline size_t
+wcrtomb (char *s, wchar_t wc, mbstate_t *ps __attribute__ ((unused)))
+{
+  if (s == 0)
+    return 1;
+  return grub_encode_utf8_character ((grub_uint8_t *) s,
+				     (grub_uint8_t *) s + MB_LEN_MAX,
+				     wc);
+}
+
+static inline wint_t btowc (int c)
+{
+  if (c & ~0x7f)
+    return WEOF;
+  return c;
+}
+
+
+static inline int
+wcscoll (const wchar_t *s1, const wchar_t *s2)
+{
+  while (*s1 && *s2)
+    {
+      if (*s1 != *s2)
+	break;
+
+      s1++;
+      s2++;
+    }
+
+  if (*s1 < *s2)
+    return -1;
+  if (*s1 > *s2)
+    return +1;
+  return 0;
+}
 
 #endif