fs/Traits: add constant CURRENT_DIRECTORY

src/fs/CheckFile.cxx

@@ -47,7 +47,8 @@ CheckDirectoryReadable(Path path_fs)
 	}
 
 #ifndef WIN32
-	const auto x = AllocatedPath::Build(path_fs, ".");
+	const auto x = AllocatedPath::Build(path_fs,
+					    PathTraitsFS::CURRENT_DIRECTORY);
 	if (!StatFile(x, st) && errno == EACCES)
 		FormatError(config_domain,
 			    "No permission to traverse (\"execute\") directory: %s",

src/fs/Traits.cxx

@@ -74,7 +74,7 @@ GetParentPathImpl(typename Traits::const_pointer p)
 
 	typename Traits::const_pointer sep = Traits::FindLastSeparator(p);
 	if (sep == nullptr)
-		return typename Traits::string(".");
+		return typename Traits::string(Traits::CURRENT_DIRECTORY);
 	if (sep == p)
 		return typename Traits::string(p, p + 1);
 #ifdef WIN32

src/fs/Traits.hxx

@@ -47,6 +47,8 @@ struct PathTraitsFS {
 	static constexpr value_type SEPARATOR = '/';
 #endif
 
+	static constexpr const_pointer CURRENT_DIRECTORY = ".";
+
 	static constexpr bool IsSeparator(value_type ch) {
 		return
 #ifdef WIN32
@@ -149,6 +151,8 @@ struct PathTraitsUTF8 {
 
 	static constexpr value_type SEPARATOR = '/';
 
+	static constexpr const_pointer CURRENT_DIRECTORY = ".";
+
 	static constexpr bool IsSeparator(value_type ch) {
 		return ch == SEPARATOR;
 	}