Define 'WINDOWS_PHONE' and 'WINDOWS_STORE' variables

Set one of these when CMAKE_SYSTEM_NAME is "WindowsPhone" or
"WindowsStore", respectively.

Help/manual/cmake-variables.7.rst

@@ -190,6 +190,8 @@ Variables that Describe the System
    /variable/MSVC_VERSION
    /variable/UNIX
    /variable/WIN32
+   /variable/WINDOWS_PHONE
+   /variable/WINDOWS_STORE
    /variable/XCODE_VERSION
 
 Variables that Control the Build

Help/variable/WINDOWS_PHONE.rst

@@ -0,0 +1,5 @@
+WINDOWS_PHONE
+-------------
+
+True when the :variable:`CMAKE_SYSTEM_NAME` variable is set
+to ``WindowsPhone``.

Help/variable/WINDOWS_STORE.rst

@@ -0,0 +1,5 @@
+WINDOWS_STORE
+-------------
+
+True when the :variable:`CMAKE_SYSTEM_NAME` variable is set
+to ``WindowsStore``.

Modules/Platform/Windows.cmake

@@ -2,6 +2,10 @@ set(WIN32 1)
 
 if(CMAKE_SYSTEM_NAME STREQUAL "WindowsCE")
   set(WINCE 1)
+elseif(CMAKE_SYSTEM_NAME STREQUAL "WindowsPhone")
+  set(WINDOWS_PHONE 1)
+elseif(CMAKE_SYSTEM_NAME STREQUAL "WindowsStore")
+  set(WINDOWS_STORE 1)
 endif()
 
 set(CMAKE_STATIC_LIBRARY_PREFIX "")