libutf: move to proper paths

include/libutf.h

@@ -0,0 +1,17 @@
+#if __STDC_VERSION__ >= 199901L
+/* C99 type definitions */
+#	include <stdint.h>
+typedef uint32_t rune_t;
+#else
+/* Must hold at least 32b; see the C89 draft 2.2.4.2
+ * <http://jfxpt.com/library/c89-draft.html#2.2.4.2> */
+typedef unsigned long int rune_t;
+#endif
+#include <stddef.h> /* size_t */
+
+rune_t swab32(rune_t c);
+rune_t utf8_to_utf32be(rune_t c);
+char *utf8_to_chars(rune_t c, char *s, size_t n);
+rune_t utf32be_to_utf8(rune_t c, size_t m);
+rune_t utf32be_to_utf32le(rune_t c);
+rune_t utf32le_to_utf32be(rune_t c);