quote: provide sq_dequote_to_argv_array

This is similar to sq_dequote_to_argv, but more convenient
if you have an argv_array. It's tempting to just feed the
components of the argv_array to sq_dequote_to_argv instead,
but:

  1. It wouldn't maintain the NULL-termination invariant
     of argv_array.

  2. It doesn't match the memory ownership policy of
     argv_array (in which each component is free-able, not a
     pointer into a separate buffer).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/quote.h b/quote.h
index 252b0df..133155a 100644
--- a/quote.h
+++ b/quote.h
@@ -45,6 +45,14 @@
  */
 extern int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc);
 
+/*
+ * Same as above, but store the unquoted strings in an argv_array. We will
+ * still modify arg in place, but unlike sq_dequote_to_argv, the argv_array
+ * will duplicate and take ownership of the strings.
+ */
+struct argv_array;
+extern int sq_dequote_to_argv_array(char *arg, struct argv_array *);
+
 extern int unquote_c_style(struct strbuf *, const char *quoted, const char **endp);
 extern size_t quote_c_style(const char *name, struct strbuf *, FILE *, int no_dq);
 extern void quote_two_c_style(struct strbuf *, const char *, const char *, int);