ast-grep: simplify `cmStrCat` calls with one-char strings

Source/cmFastbuildNormalTargetGenerator.cxx

@@ -185,7 +185,7 @@ void cmFastbuildNormalTargetGenerator::GetLinkerExecutableAndArgs(
   if (iter != compilers.end()) {
     LogMessage("Linker launcher: " + iter->first);
     outLinkerExecutable = iter->second.Executable;
-    outLinkerArgs = cmStrCat(iter->second.Args, " ", command);
+    outLinkerArgs = cmStrCat(iter->second.Args, ' ', command);
   } else {
     SplitLinkerFromArgs(command, outLinkerExecutable, outLinkerArgs);
   }
@@ -359,7 +359,7 @@ void cmFastbuildNormalTargetGenerator::ApplyLinkRuleLauncher(
     this->GetGeneratorTarget(), "RULE_LAUNCH_LINK", Config);
   if (cmNonempty(val)) {
     LogMessage("RULE_LAUNCH_LINK: " + val);
-    command = cmStrCat(val, " ", command);
+    command = cmStrCat(val, ' ', command);
   }
 }
 
@@ -550,7 +550,7 @@ void cmFastbuildNormalTargetGenerator::GenerateModuleDefinitionInfo(
     execNode.Name = target.Name + "-def-files";
     execNode.ExecExecutable = cmSystemTools::GetCMakeCommand();
     execNode.ExecArguments =
-      cmStrCat("-E __create_def ", FASTBUILD_2_INPUT_PLACEHOLDER, " ",
+      cmStrCat("-E __create_def ", FASTBUILD_2_INPUT_PLACEHOLDER, ' ',
                FASTBUILD_1_INPUT_PLACEHOLDER);
     std::string const obj_list_file = mdi->DefFile + ".objs";
 
@@ -1492,7 +1492,7 @@ void cmFastbuildNormalTargetGenerator::GenerateObjects(FastbuildTarget& target)
 
   for (auto& val : nodesPermutations) {
     auto& objectListNode = val.second;
-    objectListNode.Name = cmStrCat(objectListNode.Name, "_", ++groupNameCount);
+    objectListNode.Name = cmStrCat(objectListNode.Name, '_', ++groupNameCount);
     LogMessage(cmStrCat("ObjectList name: ", objectListNode.Name));
   }
   std::vector<FastbuildObjectListNode>& objects = target.ObjectListNodes;

Source/cmGlobalFastbuildGenerator.cxx

@@ -1631,7 +1631,7 @@ void cmGlobalFastbuildGenerator::WriteSolution()
         folderName,
         { { "Path", Quote(pathToFolder) },
           { "Projects",
-            cmStrCat("{", cmJoin(Wrap(projectsInFolder), ","), "}") } },
+            cmStrCat('{', cmJoin(Wrap(projectsInFolder), ","), '}') } },
         1);
       folders.emplace_back(std::move(folderName));
     }

Source/cmProjectCommand.cxx

@@ -273,7 +273,7 @@ bool cmProjectCommand(std::vector<std::string> const& args,
   // Note, this intentionally doesn't touch cache variables as the legacy
   // behavior did not modify cache
   auto checkAndClearVariables = [&](cm::string_view var) {
-    std::vector<std::string> vv = { "PROJECT_", cmStrCat(projectName, "_") };
+    std::vector<std::string> vv = { "PROJECT_", cmStrCat(projectName, '_') };
     if (mf.IsRootMakefile()) {
       vv.push_back("CMAKE_PROJECT_");
     }