appveyor: always use cmake `-A` option to select x64

The `Win64` generator suffix alternative was required by old CMake
versions (<3.1) only:
https://cmake.org/cmake/help/v3.22/generator/Visual%20Studio%2010%202010.html

Closes #15935

diff --git a/appveyor.yml b/appveyor.yml
index ae0fe5804294b540380914b07b2440fd560dc15d..b68ffc34db77b39c84accb93c9cd881dd816be3c 100644 (file)
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -84,7 +84,8 @@ environment:
     - job_name: 'CMake, VS2010, Debug, x64, Schannel, Static, Build-tests & examples'
       APPVEYOR_BUILD_WORKER_IMAGE: 'Visual Studio 2015'
       BUILD_SYSTEM: CMake
-      PRJ_GEN: 'Visual Studio 10 2010 Win64'
+      PRJ_GEN: 'Visual Studio 10 2010'
+      TARGET: '-A x64'
       PRJ_CFG: Debug
       SCHANNEL: 'ON'
       ENABLE_UNICODE: 'OFF'