Fixed Visual Studio precompiled headers

cmake/OpenCVPCHSupport.cmake

@@ -328,7 +328,7 @@ ENDMACRO(ADD_NATIVE_PRECOMPILED_HEADER)
 macro(ocv_add_precompiled_header_to_target the_target pch_header)
   if(PCHSupport_FOUND AND ENABLE_PRECOMPILED_HEADERS AND EXISTS "${pch_header}")
     if(CMAKE_GENERATOR MATCHES Visual)
-      set(${the_target}_pch "${pch_header}")
+      string(REGEX REPLACE "hpp$" "cpp" ${the_target}_pch "${pch_header}")
       add_native_precompiled_header(${the_target} ${pch_header})
       unset(${the_target}_pch)
     elseif(CMAKE_GENERATOR MATCHES Xcode)