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/cmAddCustomTargetCommand.cxx b/Source/cmAddCustomTargetCommand.cxx
index c14b745..caea510 100644
--- a/Source/cmAddCustomTargetCommand.cxx
+++ b/Source/cmAddCustomTargetCommand.cxx
@@ -12,6 +12,7 @@
 #include "cmMakefile.h"
 #include "cmMessageType.h"
 #include "cmStateTypes.h"
+#include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 #include "cmTarget.h"
 
@@ -122,8 +123,7 @@ bool cmAddCustomTargetCommand(std::vector<std::string> const& args,
         case doing_byproducts: {
           std::string filename;
           if (!cmSystemTools::FileIsFullPath(copy)) {
-            filename = mf.GetCurrentBinaryDirectory();
-            filename += "/";
+            filename = cmStrCat(mf.GetCurrentBinaryDirectory(), '/');
           }
           filename += copy;
           cmSystemTools::ConvertToUnixSlashes(filename);