argv-array: add a new "pushl" method

It can be convenient to push many strings in a single line
(e.g., if you are initializing an array with defaults). This
patch provides a convenience wrapper to allow this.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/argv-array.h b/argv-array.h
index c45c698..b93a69c 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -15,6 +15,7 @@
 void argv_array_push(struct argv_array *, const char *);
 __attribute__((format (printf,2,3)))
 void argv_array_pushf(struct argv_array *, const char *fmt, ...);
+void argv_array_pushl(struct argv_array *, ...);
 void argv_array_clear(struct argv_array *);
 
 #endif /* ARGV_ARRAY_H */