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, 5 deletions

diff --git a/Source/cmUtilitySourceCommand.cxx b/Source/cmUtilitySourceCommand.cxx
index b59a587cd4..d255b6795a 100644
--- a/Source/cmUtilitySourceCommand.cxx
+++ b/Source/cmUtilitySourceCommand.cxx
@@ -7,6 +7,7 @@
 #include "cmMakefile.h"
 #include "cmState.h"
 #include "cmStateTypes.h"
+#include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 
 class cmExecutionStatus;
@@ -35,11 +36,11 @@ bool cmUtilitySourceCommand::InitialPass(std::vector<std::string> const& args,
   if (this->Makefile->IsOn("CMAKE_CROSSCOMPILING")) {
     haveCacheValue = (cacheValue != nullptr);
     if (!haveCacheValue) {
-      std::string msg = "UTILITY_SOURCE is used in cross compiling mode for ";
-      msg += cacheEntry;
-      msg += ". If your intention is to run this executable, you need to "
-             "preload the cache with the full path to a version of that "
-             "program, which runs on this build machine.";
+      std::string msg = cmStrCat(
+        "UTILITY_SOURCE is used in cross compiling mode for ", cacheEntry,
+        ". If your intention is to run this executable, you need to "
+        "preload the cache with the full path to a version of that "
+        "program, which runs on this build machine.");
       cmSystemTools::Message(msg, "Warning");
     }
   } else {