refactor: move dynarray into own module

include/vieter_dynarray.h

@@ -0,0 +1,34 @@
+#ifndef VIETER_DYNARRAY
+#define VIETER_DYNARRAY
+
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct vieter_dynarray {
+  char **array;
+  size_t capacity;
+  size_t size;
+} vieter_dynarray;
+
+/*
+ * Allocate a dynamic array.
+ */
+vieter_dynarray *vieter_dynarray_init(size_t initial_capacity);
+
+/*
+ * Initialise array (if it's not already initialised) and insert a string.
+ */
+void vieter_dynarray_add(vieter_dynarray *da, const char *s);
+
+/*
+ * Deallocate dynamic array.
+ */
+void vieter_dynarray_free(vieter_dynarray *da);
+
+/*
+ * Convert a vieter_dynarray into an array by freeing all its surrounding
+ * components and returning the underlying array pointer.
+ */
+char **vieter_dynarray_convert(vieter_dynarray *da);
+
+#endif