UTF-8 support (initial commit)

src/utils/utf8.c

@@ -0,0 +1,9 @@
+#include <stddef.h>
+
+size_t count_utf8_code_points(const char *s) {
+    size_t count = 0;
+    while (*s) {
+        count += (*s++ & 0xC0) != 0x80;
+    }
+    return count;
+}

src/utils/utf8.h

@@ -0,0 +1,7 @@
+#ifndef UTF8_H
+#define UTF8_H
+
+#include <stddef.h>
+size_t count_utf8_code_points(const char *s);
+
+#endif

src/utils/utils.h

@@ -1,4 +1,5 @@
 #ifndef D_UTILS_H
 #define D_UTILS_H
 #include "d_array.h"
+#include "utf8.h"
 #endif