Format a string and push it onto the end of the array. This is a
convenience wrapper combining `strbuf_addf` and `argv_array_push`.
+`argv_array_pushv`::
+ Push a null-terminated array of strings onto the end of the array.
+
`argv_array_pop`::
Remove the final element from the array. If there are no
elements in the array, do nothing.
`argv_array_clear`::
Free all memory associated with the array and return it to the
initial, empty state.
+
+`argv_array_detach`::
+ Disconnect the `argv` member from the `argv_array` struct and
+ return it. The caller is responsible for freeing the memory used
+ by the array, and by the strings it references. After detaching,
+ the `argv_array` is in a reinitialized state and can be pushed
+ into again.