From 1129232d506897bc2f58a13a15213c4fdfc16d30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?D=C5=BEenan=20Zuki=C4=87?= <dzenan.zukic@kitware.com>
Date: Thu, 18 Nov 2021 17:41:59 -0500
Subject: [PATCH] ENH: use the new CMake mechanism to specify MSVC's static or
 DLL CRT

---
 CMake/ITKConfig.cmake.in |  3 +++
 CMake/UseITK.cmake       | 10 ++++++++++
 CMakeLists.txt           | 14 +++++++++++++-
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/CMake/ITKConfig.cmake.in b/CMake/ITKConfig.cmake.in
index f50fdd72450b..de76e4aef97b 100644
--- a/CMake/ITKConfig.cmake.in
+++ b/CMake/ITKConfig.cmake.in
@@ -50,6 +50,9 @@ set(ITK_BUILD_SHARED "@ITK_BUILD_SHARED_LIBS@")
 # Export the library build type (SHARED or STATIC) for external builds
 set(ITK_LIBRARY_BUILD_TYPE "@ITK_LIBRARY_BUILD_TYPE@")
 
+# Whether ITK links to MSVC's static CRT (/MT and /MTd).
+set(ITK_MSVC_STATIC_CRT "@ITK_MSVC_STATIC_RUNTIME_LIBRARY_value@")
+
 # Whether ITK examples were built.
 set(ITK_BUILD_EXAMPLES "@BUILD_EXAMPLES@")
 
diff --git a/CMake/UseITK.cmake b/CMake/UseITK.cmake
index 89decdb4f312..3a6586a462da 100644
--- a/CMake/UseITK.cmake
+++ b/CMake/UseITK.cmake
@@ -24,6 +24,16 @@ set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${ITK_REQUIRED_LINK_
 set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${ITK_REQUIRED_LINK_FLAGS}")
 include(${ITK_CMAKE_DIR}/ITKInitializeCXXStandard.cmake)
 
+if(MSVC)
+  if(ITK_MSVC_STATIC_CRT)
+    message(STATUS "ITK is setting ${PROJECT_NAME}'s MSVC_RUNTIME_LIBRARY to static")
+    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+  else()
+    message(STATUS "ITK is setting ${PROJECT_NAME}'s MSVC_RUNTIME_LIBRARY to dynamic")
+    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL")
+  endif()
+endif()
+
 # Add include directories needed to use ITK.
 include_directories(BEFORE ${ITK_INCLUDE_DIRS})
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0c8b85c0129f..b72d82f00ba5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,7 +29,7 @@ foreach(pnew "CMP0120")
     cmake_policy(SET ${pnew} NEW)
   endif()
 endforeach()
-foreach(pold "CMP0091")
+foreach(pold "")
   if(POLICY ${pold})
     cmake_policy(SET ${pold} OLD)
   endif()
@@ -125,6 +125,18 @@ endif()
 include(CTest)
 mark_as_advanced(CLEAR BUILD_TESTING)
 
+option(ITK_MSVC_STATIC_RUNTIME_LIBRARY "Link to MSVC's static CRT (/MT and /MTd).
+OFF (default) means link to regular, dynamic CRT (/MD and /MDd)." OFF)
+mark_as_advanced(ITK_MSVC_STATIC_RUNTIME_LIBRARY)
+set(ITK_MSVC_STATIC_RUNTIME_LIBRARY_value ${ITK_MSVC_STATIC_RUNTIME_LIBRARY})
+if(ITK_MSVC_STATIC_RUNTIME_LIBRARY)
+  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
+  message(STATUS "Using MSVC's static CRT (/MT and /MTd)")
+else()
+  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL")
+  message(STATUS "Using MSVC's dynamic CRT (/MD and /MDd)")
+endif()
+
 include(ITKDownloadSetup)
 include(PreventInSourceBuilds)
 include(PreventInBuildInstalls)