+/**
+ * The argv-array API allows one to dynamically build and store
+ * NULL-terminated lists. An argv-array maintains the invariant that the
+ * `argv` member always points to a non-NULL array, and that the array is
+ * always NULL-terminated at the element pointed to by `argv[argc]`. This
+ * makes the result suitable for passing to functions expecting to receive
+ * argv from main().
+ *
+ * The string-list API (documented in string-list.h) is similar, but cannot be
+ * used for these purposes; instead of storing a straight string pointer,
+ * it contains an item structure with a `util` field that is not compatible
+ * with the traditional argv interface.
+ *
+ * Each `argv_array` manages its own memory. Any strings pushed into the
+ * array are duplicated, and all memory is freed by argv_array_clear().
+ */
+