Initialize character set encoding on program startup

libarchive uses `nl_langinfo(CODESET)` as the host's encoding to convert
path names to/from the archive's encoding.  Since commit cd408d93fd (Add
setlocale() calls around use of libarchive APIs, 2015-02-06, v3.1.3~2^2)
we've set `LC_CTYPE` using a scoped locale around libarchive calls to
avoid affecting character classification in the rest of the program.

We've since updated the rest of our code to be locale-independent.
Replace the scoped locale with a single locale established at program
startup.  This is more efficient and avoids mutating global state.

Issue: #27562

Source/CMakeLists.txt

@@ -401,7 +401,6 @@ add_library(
   cmRulePlaceholderExpander.cxx
   cmRulePlaceholderExpander.h
   cmLocalUnixMakefileGenerator3.cxx
-  cmLocale.h
   cmMakefile.cxx
   cmMakefile.h
   cmMakefileTargetGenerator.cxx

Source/cmArchiveWrite.cxx

@@ -24,7 +24,6 @@
 
 #include "cm_parse_date.h"
 
-#include "cmLocale.h"
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 
@@ -449,9 +448,6 @@ bool cmArchiveWrite::AddFile(char const* file, size_t skip, char const* prefix)
   }
   char const* out = file + skip;
 
-  cmLocaleRAII localeRAII;
-  static_cast<void>(localeRAII);
-
   // Meta-data.
   std::string dest = cmStrCat(prefix ? prefix : "", out);
   if (this->Verbose) {

Source/cmLocale.h

@@ -1,26 +0,0 @@
-/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
-   file LICENSE.rst or https://cmake.org/licensing for details.  */
-#pragma once
-
-#include "cmConfigure.h" // IWYU pragma: keep
-
-#include <clocale>
-#include <string>
-
-class cmLocaleRAII
-{
-public:
-  cmLocaleRAII()
-    : OldLocale(setlocale(LC_CTYPE, nullptr))
-  {
-    setlocale(LC_CTYPE, "");
-  }
-
-  ~cmLocaleRAII() { setlocale(LC_CTYPE, this->OldLocale.c_str()); }
-
-  cmLocaleRAII(cmLocaleRAII const&) = delete;
-  cmLocaleRAII& operator=(cmLocaleRAII const&) = delete;
-
-private:
-  std::string OldLocale;
-};

Source/cmStdIoInit.cxx

@@ -3,6 +3,7 @@
 #include "cmStdIoInit.h"
 
 #include <cerrno>
+#include <clocale>
 #include <cstdio>
 #include <cstdlib>
 #include <iostream>
@@ -106,14 +107,19 @@ public:
   static Globals& Get();
 };
 
-#ifdef _WIN32
 Globals::Globals()
 {
+#ifdef _WIN32
+  // On Windows, setlocale offers a ".<code-page>" syntax to select the
+  // user's locale with a specific character set.  We always use UTF-8.
+  std::setlocale(LC_CTYPE, ".UTF-8");
+
   SetConsoleCtrlHandler(CtrlHandler, TRUE);
-}
 #else
-Globals::Globals() = default;
+  // On non-Windows platforms, we select the user's locale.
+  std::setlocale(LC_CTYPE, "");
 #endif
+}
 
 Globals& Globals::Get()
 {

Source/cmSystemTools.cxx

@@ -58,7 +58,6 @@
 #  include <cm3p/archive_entry.h>
 
 #  include "cmArchiveWrite.h"
-#  include "cmLocale.h"
 #  ifndef __LA_INT64_T
 #    define __LA_INT64_T la_int64_t
 #  endif
@@ -2624,8 +2623,6 @@ bool extract_tar(std::string const& arFileName,
                  cmSystemTools::cmTarExtractTimestamps extractTimestamps,
                  bool extract)
 {
-  cmLocaleRAII localeRAII;
-  static_cast<void>(localeRAII);
   struct archive* a = archive_read_new();
   struct archive* ext = archive_write_disk_new();
   if (extract) {