diff --git a/CMakeLists.txt b/CMakeLists.txt
index 98bde02b8..4508e33e1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@
 # See the License for more information.
 #=============================================================================
 CMAKE_MINIMUM_REQUIRED(VERSION 2.4.5 FATAL_ERROR)
+SET(CMAKE_LEGACY_CYGWIN_WIN32 0) # Remove when CMake >= 2.8.4 is required
 PROJECT(CMake)
 IF(COMMAND CMAKE_POLICY)
   CMAKE_POLICY(SET CMP0003 NEW)
diff --git a/Modules/Platform/CYGWIN.cmake b/Modules/Platform/CYGWIN.cmake
index 157698259..b7ad2cee1 100644
--- a/Modules/Platform/CYGWIN.cmake
+++ b/Modules/Platform/CYGWIN.cmake
@@ -1,4 +1,48 @@
-SET(WIN32 1)
+if("${CMAKE_MINIMUM_REQUIRED_VERSION}" VERSION_LESS "2.8.3.20101214")
+  set(__USE_CMAKE_LEGACY_CYGWIN_WIN32 1)
+endif()
+if(NOT DEFINED WIN32)
+  set(WIN32 0)
+  if(DEFINED __USE_CMAKE_LEGACY_CYGWIN_WIN32)
+    if(NOT DEFINED CMAKE_LEGACY_CYGWIN_WIN32
+        AND DEFINED ENV{CMAKE_LEGACY_CYGWIN_WIN32})
+      set(CMAKE_LEGACY_CYGWIN_WIN32 $ENV{CMAKE_LEGACY_CYGWIN_WIN32})
+    endif()
+    if(CMAKE_LEGACY_CYGWIN_WIN32)
+      message(STATUS "Defining WIN32 under Cygwin due to CMAKE_LEGACY_CYGWIN_WIN32")
+      set(WIN32 1)
+    elseif("x${CMAKE_LEGACY_CYGWIN_WIN32}" STREQUAL "x")
+      message(WARNING "CMake no longer defines WIN32 on Cygwin!"
+        "\n"
+        "(1) If you are just trying to build this project, ignore this warning "
+        "or quiet it by setting CMAKE_LEGACY_CYGWIN_WIN32=0 in your environment or "
+        "in the CMake cache.  "
+        "If later configuration or build errors occur then this project may "
+        "have been written under the assumption that Cygwin is WIN32.  "
+        "In that case, set CMAKE_LEGACY_CYGWIN_WIN32=1 instead."
+        "\n"
+        "(2) If you are developing this project, add the line\n"
+        "  set(CMAKE_LEGACY_CYGWIN_WIN32 0) # Remove when CMake >= 2.8.4 is required\n"
+        "at the top of your top-level CMakeLists.txt file or set the minimum "
+        "required version of CMake to 2.8.4 or higher.  "
+        "Then teach your project to build on Cygwin without WIN32.")
+    endif()
+  elseif(DEFINED CMAKE_LEGACY_CYGWIN_WIN32)
+    message(AUTHOR_WARNING "CMAKE_LEGACY_CYGWIN_WIN32 ignored because\n"
+      "  cmake_minimum_required(VERSION ${CMAKE_MINIMUM_REQUIRED_VERSION})\n"
+      "is at least 2.8.4.")
+  endif()
+endif()
+if(DEFINED __USE_CMAKE_LEGACY_CYGWIN_WIN32)
+  # Pass WIN32 legacy setting to scripts.
+  if(WIN32)
+    set(ENV{CMAKE_LEGACY_CYGWIN_WIN32} 1)
+  else()
+    set(ENV{CMAKE_LEGACY_CYGWIN_WIN32} 0)
+  endif()
+  unset(__USE_CMAKE_LEGACY_CYGWIN_WIN32)
+endif()
+
 SET(CYGWIN 1)
 
 SET(CMAKE_SHARED_LIBRARY_PREFIX "cyg")
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 56e0ed933..813258d65 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -2340,17 +2340,19 @@ void cmMakefile::AddDefaultDefinitions()
   working, these variables are still also set here in this place, but they
   will be reset in CMakeSystemSpecificInformation.cmake before the platform
   files are executed. */
-#if defined(_WIN32) || defined(__CYGWIN__)
+#if defined(_WIN32)
   this->AddDefinition("WIN32", "1");
   this->AddDefinition("CMAKE_HOST_WIN32", "1");
 #else
   this->AddDefinition("UNIX", "1");
   this->AddDefinition("CMAKE_HOST_UNIX", "1");
 #endif
-  // Cygwin is more like unix so enable the unix commands
 #if defined(__CYGWIN__)
-  this->AddDefinition("UNIX", "1");
-  this->AddDefinition("CMAKE_HOST_UNIX", "1");
+  if(cmSystemTools::IsOn(cmSystemTools::GetEnv("CMAKE_LEGACY_CYGWIN_WIN32")))
+    {
+    this->AddDefinition("WIN32", "1");
+    this->AddDefinition("CMAKE_HOST_WIN32", "1");
+    }
 #endif
 #if defined(__APPLE__)
   this->AddDefinition("APPLE", "1");