Avoid converting slashes in root names in path::lexically_normal.

lexically_normal is supposed to convert directory separators, so it
should not modify the path root name.

doc/release_history.html

@@ -41,7 +41,8 @@
 
 <h2>1.85.0</h2>
 <ul>
-  <li><code>path::generic_path</code> and <code>path::generic_string</code> methods now remove duplicate directory separators in the returned paths. The methods also avoid converting backslashes to forward slashes in root names of the paths. For example, on Windows, <code>path("\\\\?\\c:\\foo").generic_string()</code> now returns "\\?\c:/foo" instead of "//?/c:/foo". Similarly, <code>path("\\\\host\\share").generic_string()</code> now returns "\\host/share".</li>
+  <li><code>path::generic_path</code> and <code>path::generic_string</code> methods now remove duplicate directory separators in the returned paths.</li>
+  <li><code>path::generic_path</code>, <code>path::generic_string</code> and <code>path::lexically_normal</code> avoid converting between backslashes and forward slashes in path root names. For example, on Windows, <code>path("\\\\?\\c:\\foo").generic_string()</code> now returns "\\?\c:/foo" instead of "//?/c:/foo". Similarly, <code>path("\\\\host/share/foo/..").lexically_normal()</code> now returns "\\host\share".</li>
 </ul>
 
 <h2>1.84.0</h2>

src/path.cpp

@@ -174,14 +174,6 @@ BOOST_FILESYSTEM_DECL path path_algorithms::lexically_normal_v3(path const& p)
     size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
     path normal(pathname, pathname + root_name_size);
 
-#if defined(BOOST_WINDOWS_API)
-    for (size_type i = 0; i < root_name_size; ++i)
-    {
-        if (normal.m_pathname[i] == path::separator)
-            normal.m_pathname[i] = path::preferred_separator;
-    }
-#endif
-
     size_type root_path_size = root_name_size;
     if (root_dir_pos < pathname_size)
     {
@@ -272,14 +264,6 @@ BOOST_FILESYSTEM_DECL path path_algorithms::lexically_normal_v4(path const& p)
     size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
     path normal(pathname, pathname + root_name_size);
 
-#if defined(BOOST_WINDOWS_API)
-    for (size_type i = 0; i < root_name_size; ++i)
-    {
-        if (normal.m_pathname[i] == path::separator)
-            normal.m_pathname[i] = path::preferred_separator;
-    }
-#endif
-
     size_type root_path_size = root_name_size;
     if (root_dir_pos < pathname_size)
     {