Add dstr_t type

include/dstring/dstring.h

@@ -0,0 +1,19 @@
+#ifndef DSTRING_H
+#define DSTRING_H
+
+#include "aliases.h"
+
+typedef struct dstr dstr_t;
+
+dstr_t *dstr_with_capacity(u64 capacity);
+dstr_t *dstr_from_string(const char *str);
+void update_dstr(dstr_t **dst, const char *src);
+void delete_dstr(dstr_t **str);
+void concat_dstr(dstr_t **dst, const char *src);
+void append_to_dstr(dstr_t **dst, char c);
+void empty_dstr(dstr_t *str);
+void print_dstr(const dstr_t *str);
+u64 dstr_length(const dstr_t *str);
+u64 dstr_capacity(const dstr_t *str);
+
+#endif // !DSTRING_H