Restore prematurely deleted header

* include/mailutils/argcv.h: Restore
* include/mailutils/Makefile.am: Add back argcv.h

@@ -28,6 +28,7 @@ pkginclude_HEADERS = \
  acl.h\
  acl.h\
  address.h\
  address.h\
  alloc.h\
  alloc.h\
+ argcv.h\
  assoc.h\
  assoc.h\
  attribute.h\
  attribute.h\
  auth.h\
  auth.h\

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999-2001, 2005, 2007, 2010-2012, 2014-2016 Free
+   Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifndef _ARGCV_H
+#define _ARGCV_H 1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <mailutils/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void mu_argcv_free (size_t argc, char **argv);
+void mu_argv_free (char **argv);
+
+enum mu_argcv_escape
+  {
+    mu_argcv_escape_no,
+    mu_argcv_escape_c
+    /*    mu_argcv_escape_sh */
+  };
+
+int mu_argcv_join (int argc, char **argv, char *delim,
+		   enum mu_argcv_escape esc,
+		   char **pstring);
+void mu_argcv_remove (int *pargc, char ***pargv,
+		      int (*sel) (const char *, void *), void *);
+int mu_argcv_string (int argc, char **argv, char **string);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _ARGCV_H */