cmake: Teach "-E tar" command a "--mtime=" option

Add an option to set the mtime of entries in a tarball so that one can
create a tarball with a consistent content hash (e.g. MD5) for a given
set of files regardless of their current timestamps on disk.  This will
be useful for submission of tarballs to CDash, which tracks content
hashes to avoid duplication.

Inspired-by: Bill Hoffman <bill.hoffman@kitware.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/Source/cm_get_date.h b/Source/cm_get_date.h
new file mode 100644
index 0000000..d5f6d3e
--- /dev/null
+++ b/Source/cm_get_date.h
@@ -0,0 +1,28 @@
+/*============================================================================
+  CMake - Cross Platform Makefile Generator
+  Copyright 2000-2015 Kitware, Inc.
+
+  Distributed under the OSI-approved BSD License (the "License");
+  see accompanying file Copyright.txt for details.
+
+  This software is distributed WITHOUT ANY WARRANTY; without even the
+  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+  See the License for more information.
+============================================================================*/
+#ifndef cm_get_date_h
+#define cm_get_date_h
+
+#include <time.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Parse a date/time string.  Treat relative times with respect to 'now'. */
+time_t cm_get_date(time_t now, const char *str);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif