install, mkdir: Handle dir/./ like dir/.

The dir/. special case was handled correctly, but dir/./ was not,
breaking gcc builds, which run:

../../../../src/libstdc++-v3/../install-sh -c -d debug/./

Bug-Ubuntu: https://bugs.launchpad.net/bugs/2117466

src/uucore/src/lib/features/fs.rs

@@ -534,12 +534,12 @@ pub fn display_permissions_unix(mode: mode_t, display_file_type: bool) -> String
     result
 }
 
-/// For some programs like install or mkdir, dir/. can be provided
+/// For some programs like install or mkdir, dir/. or dir/./ can be provided
 /// Special case to match GNU's behavior:
-/// install -d foo/. should work and just create foo/
+/// install -d foo/. (and foo/./) should work and just create foo/
 /// std::fs::create_dir("foo/."); fails in pure Rust
 pub fn dir_strip_dot_for_creation(path: &Path) -> PathBuf {
-    if path.to_string_lossy().ends_with("/.") {
+    if path.to_string_lossy().ends_with("/.") || path.to_string_lossy().ends_with("/./") {
         // Do a simple dance to strip the "/."
         Path::new(&path).components().collect::<PathBuf>()
     } else {

tests/by-util/test_install.rs

@@ -1518,6 +1518,13 @@ fn test_install_dir_dot() {
         .arg("-v")
         .succeeds()
         .stdout_contains("creating directory 'dir5/cali'");
+    scene
+        .ucmd()
+        .arg("-d")
+        .arg("dir6/./")
+        .arg("-v")
+        .succeeds()
+        .stdout_contains("creating directory 'dir6'");
 
     let at = &scene.fixtures;
 
@@ -1526,6 +1533,7 @@ fn test_install_dir_dot() {
     assert!(at.dir_exists("dir3"));
     assert!(at.dir_exists("dir4/cal"));
     assert!(at.dir_exists("dir5/cali"));
+    assert!(at.dir_exists("dir6"));
 }
 
 #[test]

tests/by-util/test_mkdir.rs

@@ -332,6 +332,22 @@ fn test_mkdir_trailing_dot() {
     println!("ls dest {}", result.stdout_str());
 }
 
+#[test]
+fn test_mkdir_trailing_dot_and_slash() {
+    new_ucmd!().arg("-p").arg("-v").arg("test_dir").succeeds();
+
+    new_ucmd!()
+        .arg("-p")
+        .arg("-v")
+        .arg("test_dir_a/./")
+        .succeeds()
+        .stdout_contains("created directory 'test_dir_a'");
+
+    let scene = TestScenario::new("ls");
+    let result = scene.ucmd().arg("-al").run();
+    println!("ls dest {}", result.stdout_str());
+}
+
 #[test]
 #[cfg(not(windows))]
 fn test_umask_compliance() {