AppVeyor: Exclude new lit-test linking/link_internally.d for LLD < 6

Author: kinke

appveyor.yml

@@ -131,6 +131,9 @@ test_script:
   # Build and run LDC D unittests
   - ctest --output-on-failure -R "ldc2-unittest"
   # Run LIT testsuite
+  # Exclude linking/link_internally.d with LLD < 6 due to a magic symbol
+  # required since VS 2017 v15.5 (see https://reviews.llvm.org/D41089).
+  - ps: If ($($Env:LLVM_VERSION[0]) -lt '6') { del tests\linking\link_internally.d }
   - ctest -V -R "lit-tests"
   # Run DMD testsuite
   - if "%APPVEYOR_JOB_ARCH%"=="x64" ( set OS=Win_64) else ( set OS=Win_32)