Merge pull request #3805 from nitsch:fix-mingw-cmake-config

cmake/OpenCVConfig.cmake

@@ -86,7 +86,7 @@ elseif(MINGW)
   execute_process(COMMAND ${CMAKE_CXX_COMPILER} -dumpmachine
                   OUTPUT_VARIABLE OPENCV_GCC_TARGET_MACHINE
                   OUTPUT_STRIP_TRAILING_WHITESPACE)
-  if(CMAKE_OPENCV_GCC_TARGET_MACHINE MATCHES "64")
+  if(OPENCV_GCC_TARGET_MACHINE MATCHES "amd64|x86_64|AMD64")
     set(MINGW64 1)
     set(OpenCV_ARCH x64)
   else()

cmake/OpenCVDetectCXXCompiler.cmake

@@ -91,9 +91,9 @@ elseif(CMAKE_COMPILER_IS_GNUCXX)
 
   if(WIN32)
     execute_process(COMMAND ${CMAKE_CXX_COMPILER} -dumpmachine
-              OUTPUT_VARIABLE CMAKE_OPENCV_GCC_TARGET_MACHINE
+              OUTPUT_VARIABLE OPENCV_GCC_TARGET_MACHINE
               OUTPUT_STRIP_TRAILING_WHITESPACE)
-    if(CMAKE_OPENCV_GCC_TARGET_MACHINE MATCHES "amd64|x86_64|AMD64")
+    if(OPENCV_GCC_TARGET_MACHINE MATCHES "amd64|x86_64|AMD64")
       set(MINGW64 1)
     endif()
   endif()