Source sweep: Use cmStrCat for string concatenation

This patch is generated by a python script that uses regular expressions to
search for string concatenation patterns of the kind

```
std::string str = <ARG0>;
str += <ARG1>;
str += <ARG2>;
...
```

and replaces them with a single `cmStrCat` call

```
std::string str = cmStrCat(<ARG0>, <ARG1>, <ARG2>, ...);
```

If any `<ARGX>` is itself a concatenated string of the kind

```
a + b + c + ...;
```

then `<ARGX>` is split into multiple arguments for the `cmStrCat` call.

If there's a sequence of literals in the `<ARGX>`, then all literals in the
sequence are concatenated and merged into a single literal argument for
the `cmStrCat` call.

Single character strings are converted to single char arguments for
the `cmStrCat` call.

`std::to_string(...)` wrappings are removed from `cmStrCat` arguments,
because it supports numeric types as well as string types.

`arg.substr(x)` arguments to `cmStrCat` are replaced with
`cm::string_view(arg).substr(x)`

1 files changed, 6 insertions, 14 deletions

diff --git a/Source/cmQtAutoGenGlobalInitializer.cxx b/Source/cmQtAutoGenGlobalInitializer.cxx
index 21de8c6..abc69d0 100644
--- a/Source/cmQtAutoGenGlobalInitializer.cxx
+++ b/Source/cmQtAutoGenGlobalInitializer.cxx
@@ -211,11 +211,8 @@ cmQtAutoGenGlobalInitializer::GetCompilerFeatures(
 
   // Check if the executable exists
   if (!cmSystemTools::FileExists(executable, true)) {
-    error = "The \"";
-    error += generator;
-    error += "\" executable ";
-    error += cmQtAutoGen::Quoted(executable);
-    error += " does not exist.";
+    error = cmStrCat("The \"", generator, "\" executable ",
+                     cmQtAutoGen::Quoted(executable), " does not exist.");
     return cmQtAutoGen::CompilerFeaturesHandle();
   }
 
@@ -231,15 +228,10 @@ cmQtAutoGenGlobalInitializer::GetCompilerFeatures(
       command, &stdOut, &stdErr, &retVal, nullptr, cmSystemTools::OUTPUT_NONE,
       cmDuration::zero(), cmProcessOutput::Auto);
     if (!runResult) {
-      error = "Test run of \"";
-      error += generator;
-      error += "\" executable ";
-      error += cmQtAutoGen::Quoted(executable) + " failed.\n";
-      error += cmQtAutoGen::QuotedCommand(command);
-      error += "\n";
-      error += stdOut;
-      error += "\n";
-      error += stdErr;
+      error = cmStrCat("Test run of \"", generator, "\" executable ",
+                       cmQtAutoGen::Quoted(executable), " failed.\n",
+                       cmQtAutoGen::QuotedCommand(command), '\n', stdOut, '\n',
+                       stdErr);
       return cmQtAutoGen::CompilerFeaturesHandle();
     }
   }