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, 4 deletions

diff --git a/Source/cmGlobalVisualStudio71Generator.cxx b/Source/cmGlobalVisualStudio71Generator.cxx
index e0d86ca..e8e9ece 100644
--- a/Source/cmGlobalVisualStudio71Generator.cxx
+++ b/Source/cmGlobalVisualStudio71Generator.cxx
@@ -145,10 +145,8 @@ void cmGlobalVisualStudio71Generator::WriteProjectDepends(
   for (std::string const& name : depends) {
     std::string guid = this->GetGUID(name);
     if (guid.empty()) {
-      std::string m = "Target: ";
-      m += target->GetName();
-      m += " depends on unknown target: ";
-      m += name;
+      std::string m = cmStrCat("Target: ", target->GetName(),
+                               " depends on unknown target: ", name);
       cmSystemTools::Error(m);
     }
     fout << "\t\t{" << guid << "} = {" << guid << "}\n";