Clean a few string conversions

Source/CPack/cmCPackGenerator.cxx

@@ -829,7 +829,7 @@ int cmCPackGenerator::InstallCMakeProject(
      *     - Because it was already used for component install
      *       in order to put things in subdirs...
      */
-    cmSystemTools::PutEnv(std::string("DESTDIR=") + tempInstallDirectory);
+    cmSystemTools::PutEnv("DESTDIR=" + tempInstallDirectory);
     cmCPackLogger(cmCPackLog::LOG_DEBUG,
                   "- Creating directory: '" << dir << "'" << std::endl);
 

Source/cmSystemTools.cxx

@@ -1213,7 +1213,7 @@ bool cmSystemTools::UnsetEnv(const char* value)
 {
 #  if !defined(HAVE_UNSETENV)
   std::string var = cmStrCat(value, '=');
-  return cmSystemTools::PutEnv(var.c_str());
+  return cmSystemTools::PutEnv(var);
 #  else
   unsetenv(value);
   return true;

Source/cmXCodeScheme.cxx

@@ -33,7 +33,7 @@ void cmXCodeScheme::WriteXCodeSharedScheme(const std::string& xcProjDir,
   // Create shared scheme sub-directory tree
   //
   std::string xcodeSchemeDir = cmStrCat(xcProjDir, "/xcshareddata/xcschemes");
-  cmSystemTools::MakeDirectory(xcodeSchemeDir.c_str());
+  cmSystemTools::MakeDirectory(xcodeSchemeDir);
 
   std::string xcodeSchemeFile =
     cmStrCat(xcodeSchemeDir, '/', this->TargetName, ".xcscheme");

Source/cmake.cxx

@@ -1371,7 +1371,7 @@ struct SaveCacheEntry
 
 int cmake::HandleDeleteCacheVariables(const std::string& var)
 {
-  std::vector<std::string> argsSplit = cmExpandedList(std::string(var), true);
+  std::vector<std::string> argsSplit = cmExpandedList(var, true);
   // erase the property to avoid infinite recursion
   this->State->SetGlobalProperty("__CMAKE_DELETE_CACHE_CHANGE_VARS_", "");
   if (this->State->GetIsInTryCompile()) {

Source/cmcmd.cxx

@@ -600,8 +600,7 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string> const& args)
       }
       cmsys::ifstream fin(args[3].c_str(), std::ios::in | std::ios::binary);
       if (!fin) {
-        std::cerr << "could not open object list file: " << args[3].c_str()
-                  << "\n";
+        std::cerr << "could not open object list file: " << args[3] << "\n";
         return 1;
       }
       std::vector<std::string> files;
@@ -624,13 +623,12 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string> const& args)
       }
       FILE* fout = cmsys::SystemTools::Fopen(args[2], "w+");
       if (!fout) {
-        std::cerr << "could not open output .def file: " << args[2].c_str()
-                  << "\n";
+        std::cerr << "could not open output .def file: " << args[2] << "\n";
         return 1;
       }
       bindexplib deffile;
       if (args.size() >= 5) {
-        auto a = args[4];
+        std::string const& a = args[4];
         if (cmHasLiteralPrefix(a, "--nm=")) {
           deffile.SetNmPath(a.substr(5));
           std::cerr << a.substr(5) << "\n";
@@ -638,7 +636,7 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string> const& args)
           std::cerr << "unknown argument: " << a << "\n";
         }
       }
-      for (auto const& file : files) {
+      for (std::string const& file : files) {
         std::string const& ext = cmSystemTools::GetFilenameLastExtension(file);
         if (cmSystemTools::LowerCase(ext) == ".def") {
           if (!deffile.AddDefinitionFile(file.c_str())) {
@@ -1020,7 +1018,7 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string> const& args)
     // Command to create a symbolic link.  Fails on platforms not
     // supporting them.
     if (args[1] == "create_symlink" && args.size() == 4) {
-      const char* destinationFileName = args[3].c_str();
+      std::string const& destinationFileName = args[3];
       if ((cmSystemTools::FileExists(destinationFileName) ||
            cmSystemTools::FileIsSymlink(destinationFileName)) &&
           !cmSystemTools::RemoveFile(destinationFileName)) {
@@ -1377,15 +1375,12 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string> const& args)
 #if defined(_WIN32) && !defined(__CYGWIN__)
     // Write registry value
     if (args[1] == "write_regv" && args.size() > 3) {
-      return cmSystemTools::WriteRegistryValue(args[2].c_str(),
-                                               args[3].c_str())
-        ? 0
-        : 1;
+      return cmSystemTools::WriteRegistryValue(args[2], args[3]) ? 0 : 1;
     }
 
     // Delete registry value
     if (args[1] == "delete_regv" && args.size() > 2) {
-      return cmSystemTools::DeleteRegistryValue(args[2].c_str()) ? 0 : 1;
+      return cmSystemTools::DeleteRegistryValue(args[2]) ? 0 : 1;
     }
 
     // Remove file