Fallback to the MSVC linker until vcpkg has been updated

appveyor.yml

@@ -32,7 +32,6 @@ matrix:
 
 cache:
   - C:\cmake-3.8.0-win32-x86
-  - C:\Tools\vcpkg
 
 install:
   - ps: |
@@ -43,15 +42,6 @@ install:
         }
         $env:PATH="C:\cmake-3.8.0-win32-x86\bin;$env:PATH"
       }
-      # Until vcpkg has been updated.
-      # Note: vcpkg can also be removed from "cache".
-      if ($env:USE_TOOLSET -eq "LLVM" -and
-          (Get-Content C:\Tools\vcpkg\toolsrc\VERSION.txt).Replace('.','').Trim('"') -lt 20181020
-      ) {
-        cd C:\Tools\vcpkg
-        git pull
-        cd "$env:APPVEYOR_BUILD_FOLDER"
-      }
 
 before_build:
   - ps: |
@@ -67,8 +57,19 @@ before_build:
       }
       echo generator="$env:generator"
       if ($env:USE_TOOLSET -eq "LLVM") {
+          $LINKER = "lld-link"
+          # Workaround for lld bug with vcpkg integration
+          if ((Get-Content C:\Tools\vcpkg\toolsrc\VERSION.txt).Replace('.','').Trim('"') -lt 20181020) {
+              if ($env:PLATFORM -eq "x64") {
+                  call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
+              } else {
+                  call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars32.bat"
+              }
+              $LINKER = "link.exe" # MSVC-linker
+          } else { echo "==> vcpkg has been updated, please remove workaround from appvayor.yml." }
+          # /Workaround
           clang-cl --version
-          cmake .. -G "$env:generator" -T llvm -DGSL_CXX_STANDARD="$env:GSL_CXX_STANDARD" -DCMAKE_CXX_COMPILER=clang-cl  -DCMAKE_LINKER=lld-link
+          cmake .. -G "$env:generator" -T llvm -DGSL_CXX_STANDARD="$env:GSL_CXX_STANDARD" -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_LINKER=$LINKER
       }
       else {
           cmake .. -G "$env:generator" -DGSL_CXX_STANDARD="$env:GSL_CXX_STANDARD"