contrib/windows: update README

Move idea of hwloc-ps to a github issue.
Update some comments, add details for command-line build.

Thanks to Eloi Gaudry for the suggestion.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
(cherry picked from commit a0d8a72)

contrib/windows/README

@@ -1,33 +1,19 @@
 This Visual Studio support is experimental.
-Thanks to Eloi Gaudry for contributing the first draft of files.
+Thanks to Eloi Gaudry for contributing most of these files.
 
+This may be directly open in VS, or built from the command-line with:
+  %MSBUILD_PATH%\MSBuild hwloc.sln /p:Configuration=Release /p:Platform=x64
 
-No PlatformToolset is specified, so that the default target is always
-used during build.
-That means your build may not be compatible with older systems.
-Enforce a specific toolset before building if needed.
+If the specified platform toolset is too recent for your VS installation:
+  "The builds tools for v142 (Platform Toolset = 'v142') cannot be found."
+You may force the build using your old one by adding
+    /p:PlatformToolset=v110
 
+See contrib/ci.inria.fr/job-1-visualstudio.bat for an example.
 
-hwloc-compress-dir not built because needs work.
+
+hwloc-compress-dir not built because it needs work.
 
 hwloc-gather-topology is Linux specific.
 
-hwloc-ps is not built because it does nothing on Windows anyway.
-Possible code proposed by Eloi Gaudry:
-  // Get the process list snapshot
-  HANDLE hProcessSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPALL, 0);
-  // Initialize the process entry structure
-  PROCESSENTRY32 ProcessEntry = { 0 } ;
-  ProcessEntry.dwSize = sizeof(ProcessEntry);
-  // Get the first process info
-  if (Process32First( hProcessSnapShot, &ProcessEntry)) {
-    do {
-      HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, ProcessEntry.th32ProcessID) ;
-      if (hProcess) {
-        std::cerr << ProcessEntry.th32ProcessID << "(" << ProcessEntry.szExeFile << ")" << std::endl ;
-      }
-      // check the PROCESSENTRY32 for other members.
-    } while (Process32Next(hProcessSnapShot, &ProcessEntry));
-    // Close the handle
-    CloseHandle( hProcessSnapShot ) ;
-  }
+hwloc-ps is not built because it does nothing on Windows anyway (see #367).