Closes #18. Change to char32_t everywhere; builds fine, behaviour as before.

src/c/payloads/character.h

@@ -22,6 +22,7 @@
 /*
  * wide characters
  */
+#include <uchar.h>
 #include <wchar.h>
 #include <wctype.h>
 
@@ -33,7 +34,7 @@
  * @brief a single character, as returned by the reader.
  */
 struct character_payload {
-    wchar_t character;
+    char32_t character;
 };
 
 struct pso_pointer make_character( wint_t c );