ENH: Support object lists longer than 128K on MSVC

We use response files to list object files for the MSVC linker.  The
linker complains if any response file is greater than 128K, so we split
the object file lists into multiple response files.

Source/cmMakefileTargetGenerator.cxx

@@ -1634,14 +1634,35 @@ cmMakefileTargetGenerator
   this->WriteObjectsVariable(variableName, variableNameExternal);
   if(useResponseFile)
     {
-    std::string objects;
+    // MSVC response files cannot exceed 128K.
-    this->WriteObjectsString(objects);
+    std::string::size_type const responseFileLimit = 131000;
-    std::string objects_rsp =
+
-      this->CreateResponseFile("objects.rsp", objects, makefile_depends);
+    // Construct the individual object list strings.
-    buildObjs = "@";
+    std::vector<std::string> object_strings;
-    buildObjs += this->Convert(objects_rsp.c_str(),
+    this->WriteObjectsStrings(object_strings, responseFileLimit);
-                               cmLocalGenerator::NONE,
+
-                               cmLocalGenerator::SHELL);
+    // Write a response file for each string.
+    const char* sep = "";
+    for(unsigned int i = 0; i < object_strings.size(); ++i)
+      {
+      // Number the response files.
+      char rsp[32];
+      sprintf(rsp, "objects%u.rsp", i+1);
+
+      // Create this response file.
+      std::string objects_rsp =
+        this->CreateResponseFile(rsp, object_strings[i], makefile_depends);
+
+      // Separate from previous response file references.
+      buildObjs += sep;
+      sep = " ";
+
+      // Reference the response file.
+      buildObjs += "@";
+      buildObjs += this->Convert(objects_rsp.c_str(),
+                                 cmLocalGenerator::NONE,
+                                 cmLocalGenerator::SHELL);
+      }
     }
   else if(useLinkScript)
     {