Fix appveyor behavior for CMAKE 4.1+

Author: AzothAmmo

scripts/appveyor.bat

@@ -65,14 +65,33 @@ if "%~1" == "test" (
 )
 
 if "%PLATFORM%" == "x64" (
-    @rem please excuse the hack - CMake is unable to produce multiarch MSVC projects
-    cmake -G "%CMAKE_GENERATOR_PREFIX%" -DBOOST_ROOT=%BOOST_ROOT% -DBOOST_LIBRARYDIR=%BOOST_LIBRARYDIR% ..
+    @rem Enable legacy FindBoost behavior and restore BOOST_ROOT handling required by CMake 3.30+/4.x
+    cmake -G "%CMAKE_GENERATOR_PREFIX%" ^
+      -DCMAKE_POLICY_DEFAULT_CMP0144=NEW ^
+      -DCMAKE_POLICY_DEFAULT_CMP0167=OLD ^
+      -DBOOST_ROOT="%BOOST_ROOT%" ^
+      -DBoost_INCLUDE_DIR="%BOOST_ROOT%" ^
+      -DBoost_NO_SYSTEM_PATHS=ON ^
+      -DBoost_USE_STATIC_LIBS=OFF ^
+      -DBoost_USE_STATIC_RUNTIME=OFF ^
+      -DBoost_USE_MULTITHREADED=OFF ^
+      ..
+
     cmake --build . --config %CONFIGURATION% --target portability_test32
     del CMakeCache.txt
     rmdir /s /q CMakeFiles
 )
 
-cmake -G "%CMAKE_GENERATOR_PREFIX%" -A %PLATFORM% -DBOOST_ROOT=%BOOST_ROOT% -DBOOST_LIBRARYDIR=%BOOST_LIBRARYDIR% ..
+cmake -G "%CMAKE_GENERATOR_PREFIX%" -A %PLATFORM% ^
+  -DCMAKE_POLICY_DEFAULT_CMP0144=NEW ^
+  -DCMAKE_POLICY_DEFAULT_CMP0167=OLD ^
+  -DBOOST_ROOT="%BOOST_ROOT%" ^
+  -DBoost_INCLUDE_DIR="%BOOST_ROOT%" ^
+  -DBoost_NO_SYSTEM_PATHS=ON ^
+  -DBoost_USE_STATIC_LIBS=OFF ^
+  -DBoost_USE_STATIC_RUNTIME=OFF ^
+  -DBoost_USE_MULTITHREADED=OFF ^
+  ..
 @rem left the actual build for later - AppVeyor enables parallel jobs in a much cleaner way than msbuild
 
 :done