Allow compiling with Visual Studio 2019

Author: jairbubbles

build.libgit2.ps1

@@ -124,7 +124,12 @@ try {
     cd ..
     Run-Command -Quiet { & mkdir build64 }
     cd build64
-    Run-Command -Quiet -Fatal { & $cmake -G "Visual Studio $vs Win64" -D THREADSAFE=ON -D ENABLE_TRACE=ON -D "BUILD_CLAR=$build_clar" -D "LIBGIT2_FILENAME=$binaryFilename" ../.. }
+    if ($vs -eq "16") {
+        Run-Command -Quiet -Fatal { & $cmake -G "Visual Studio $vs" -A x64 -D THREADSAFE=ON -D ENABLE_TRACE=ON -D "BUILD_CLAR=$build_clar" -D "LIBGIT2_FILENAME=$binaryFilename" ../.. }
+    }
+    else {
+        Run-Command -Quiet -Fatal { & $cmake -G "Visual Studio $vs Win64" -D THREADSAFE=ON -D ENABLE_TRACE=ON -D "BUILD_CLAR=$build_clar" -D "LIBGIT2_FILENAME=$binaryFilename" ../.. }        
+    }
     Run-Command -Quiet -Fatal { & $cmake --build . --config $configuration }
     if ($test.IsPresent) { Run-Command -Quiet -Fatal { & $ctest -V . } }
     cd $configuration