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, 2 insertions, 2 deletions

diff --git a/Source/cmOptionCommand.cxx b/Source/cmOptionCommand.cxx
index 21841c8..a0a0989 100644
--- a/Source/cmOptionCommand.cxx
+++ b/Source/cmOptionCommand.cxx
@@ -19,8 +19,8 @@ bool cmOptionCommand(std::vector<std::string> const& args,
 {
   const bool argError = (args.size() < 2) || (args.size() > 3);
   if (argError) {
-    std::string m = "called with incorrect number of arguments: ";
-    m += cmJoin(args, " ");
+    std::string m = cmStrCat("called with incorrect number of arguments: ",
+                             cmJoin(args, " "));
     status.SetError(m);
     return false;
   }