[vala] posix: add ctime(3)

[Dr. Michael Lauer <mlauer src gnome org>]

commit 2ae0ebc8aa27ea4bf0a264432e7a64c8f9fe258b
Author: Dr. Michael Lauer <mickey vanille-media de>
Date:   Tue Jan 16 17:06:31 2018 +0100

    posix: add ctime(3)

 vapi/posix.vapi |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/vapi/posix.vapi b/vapi/posix.vapi
index 93e043c..b9ef0b0 100644
--- a/vapi/posix.vapi
+++ b/vapi/posix.vapi
@@ -1954,6 +1954,9 @@ namespace Posix {
                public clock_t ();
        }
 
+       [CCode (cheader_filename = "time.h")]
+       public unowned string? ctime (ref time_t clock);
+
        [CCode (cname = "struct tm", cheader_filename = "time.h", has_type_id = false)]
        public struct tm {
                public int tm_sec;