VS: Provide an option to use x64 host tools

Visual Studio provides toolchains that are themselves built for 32-bit
or 64-bit host architectures.  By default it uses the 32-bit tools, but
it can be told to prefer the 64-bit tools on 64-bit hosts.  Extend the
`CMAKE_GENERATOR_TOOLSET` specification to provide a way to request
use of the 64-bit host tools.

Closes: #15622

1 files changed, 9 insertions, 0 deletions

diff --git a/Source/cmVisualStudio10TargetGenerator.cxx b/Source/cmVisualStudio10TargetGenerator.cxx
index 6690bfa..4a9df04 100644
--- a/Source/cmVisualStudio10TargetGenerator.cxx
+++ b/Source/cmVisualStudio10TargetGenerator.cxx
@@ -322,6 +322,15 @@ void cmVisualStudio10TargetGenerator::Generate()
     this->WriteString("</PropertyGroup>\n", 1);
   }
 
+  if (const char* hostArch =
+        this->GlobalGenerator->GetPlatformToolsetHostArchitecture()) {
+    this->WriteString("<PropertyGroup>\n", 1);
+    this->WriteString("<PreferredToolArchitecture>", 2);
+    (*this->BuildFileStream) << cmVS10EscapeXML(hostArch)
+                             << "</PreferredToolArchitecture>\n";
+    this->WriteString("</PropertyGroup>\n", 1);
+  }
+
   this->WriteProjectConfigurations();
   this->WriteString("<PropertyGroup Label=\"Globals\">\n", 1);
   this->WriteString("<ProjectGUID>", 2);