From 7459388dd90b7fa0f94bd09ebc80c4444addbbd4 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.alekhin@intel.com>
Date: Wed, 13 Dec 2017 15:16:03 +0300
Subject: [PATCH] cmake: update timestamp status

- avoid unnecessary rebuilding of OpenCV libraries
- use timestamp of the first launch of CMake
- to return to previous behavior use `-UOPENCV_TIMESTAMP` CMake option

original commit: 3e45795232c34f45769a90c2d03482947af4084d
---
 CMakeLists.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa585b20b7..90e16c2a57 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -683,6 +683,16 @@ endif()
 # ========================== build platform ==========================
 status("")
 status("  Platform:")
+if(NOT DEFINED OPENCV_TIMESTAMP
+    AND NOT CMAKE_VERSION VERSION_LESS 2.8.11
+    AND NOT BUILD_INFO_SKIP_TIMESTAMP
+)
+  string(TIMESTAMP OPENCV_TIMESTAMP "" UTC)
+  set(OPENCV_TIMESTAMP "${OPENCV_TIMESTAMP}" CACHE STRING "Timestamp of OpenCV build configuration" FORCE)
+endif()
+if(OPENCV_TIMESTAMP)
+  status("    Timestamp:"      ${OPENCV_TIMESTAMP})
+endif()
 status("    Host:"             ${CMAKE_HOST_SYSTEM_NAME} ${CMAKE_HOST_SYSTEM_VERSION} ${CMAKE_HOST_SYSTEM_PROCESSOR})
 if(CMAKE_CROSSCOMPILING)
   status("    Target:"         ${CMAKE_SYSTEM_NAME} ${CMAKE_SYSTEM_VERSION} ${CMAKE_SYSTEM_PROCESSOR})