Fixed nesting environment variable expansion in AppVeyor.

appveyor.yml

@@ -35,7 +35,7 @@ environment:
   DEPS_PATH: '%APPVEYOR_BUILD_FOLDER%\deps'
   LLVM_PATH: '%APPVEYOR_BUILD_FOLDER%\deps\llvm'
   BUILD_PATH: '%APPVEYOR_BUILD_FOLDER%\build\%VS_VERSION%'
-  LIB_PATH: '%BUILD_PATH%\lib\%CONFIGURATION%_%BUILD_PLATFORM%'
+  LIB_PATH: '%APPVEYOR_BUILD_FOLDER%\build\%VS_VERSION%\lib\%CONFIGURATION%_%BUILD_PLATFORM%'
   ARTIFACT_NAME: '%APPVEYOR_PROJECT_NAME%-%VS_VERSION%-%APPVEYOR_REPO_BRANCH%-%APPVEYOR_BUILD_NUMBER%.zip'
   GITHUB_ACCESS_TOKEN:
     secure: CrxPDgxTKC9ZRvFjttpRPO+e1DT8s0Zkk9HrAmHOIzDkOfFbbu1iTm/yJjZ2eDcd