VS: Use .sln parser to build targets in subdirs with msbuild (#13623)

Use cmVisualStudioSlnParser in GenerateBuildCommand() to provide correct
command line for MSBuild even when target project is stored in a
subdirectory.

Source/cmGlobalVisualStudio10Generator.cxx

@@ -14,6 +14,8 @@
 #include "cmLocalVisualStudio10Generator.h"
 #include "cmMakefile.h"
 #include "cmSourceFile.h"
+#include "cmVisualStudioSlnData.h"
+#include "cmVisualStudioSlnParser.h"
 #include "cmake.h"
 
 static const char vs10Win32generatorName[] = "Visual Studio 10";
@@ -259,9 +261,38 @@ std::string cmGlobalVisualStudio10Generator
     }
   else
     {
+    std::string targetProject(targetName);
+    targetProject += ".vcxproj";
+    if (targetProject.find('/') == std::string::npos)
+      {
+      // it might be in a subdir
+      cmVisualStudioSlnParser parser;
+      cmSlnData slnData;
+      std::string slnFile;
+      if (projectDir && *projectDir)
+        {
+        slnFile = projectDir;
+        slnFile += '/';
+        slnFile += projectName;
+        }
+      else
+        {
+        slnFile = projectName;
+        }
+      if (parser.ParseFile(slnFile + ".sln", slnData,
+                           cmVisualStudioSlnParser::DataGroupProjects))
+        {
+        if (cmSlnProjectEntry const* proj =
+            slnData.GetProjectByName(targetName))
+          {
+          targetProject = proj->GetRelativePath();
+          cmSystemTools::ConvertToUnixSlashes(targetProject);
+          }
+        }
+      }
+    makeCommand += " ";
+    makeCommand += targetProject;
     makeCommand += " ";
-    makeCommand += targetName;
-    makeCommand += ".vcxproj ";
     }
   makeCommand += "/p:Configuration=";
   if(config && strlen(config))