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, 3 insertions, 5 deletions

diff --git a/Source/cmOrderDirectories.cxx b/Source/cmOrderDirectories.cxx
index 2d055ff17d..21a17e8324 100644
--- a/Source/cmOrderDirectories.cxx
+++ b/Source/cmOrderDirectories.cxx
@@ -6,6 +6,7 @@
 #include "cmGeneratorTarget.h"
 #include "cmGlobalGenerator.h"
 #include "cmMessageType.h"
+#include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 #include "cmake.h"
 
@@ -117,9 +118,7 @@ bool cmOrderDirectoriesConstraint::FileMayConflict(std::string const& dir,
                                                    std::string const& name)
 {
   // Check if the file exists on disk.
-  std::string file = dir;
-  file += "/";
-  file += name;
+  std::string file = cmStrCat(dir, '/', name);
   if (cmSystemTools::FileExists(file, true)) {
     // The file conflicts only if it is not the same as the original
     // file due to a symlink or hardlink.
@@ -229,8 +228,7 @@ bool cmOrderDirectoriesConstraintLibrary::FindConflict(std::string const& dir)
     std::string ext = this->OD->RemoveLibraryExtension.match(2);
     for (std::string const& LinkExtension : this->OD->LinkExtensions) {
       if (LinkExtension != ext) {
-        std::string fname = lib;
-        fname += LinkExtension;
+        std::string fname = cmStrCat(lib, LinkExtension);
         if (this->FileMayConflict(dir, fname)) {
           return true;
         }