enumerator: Fall back to lstat() if stat() fails when enumerating dirs/files

This happens e.g. if the path is for an invalid symlink.

src/libstrongswan/collections/enumerator.c

@@ -129,9 +129,10 @@ METHOD(enumerator_t, enumerate_dir_enum, bool,
 		{
 			*absolute = this->full;
 		}
-		if (st)
+		if (st && stat(this->full, st))
 		{
-			if (stat(this->full, st))
+			/* try lstat() e.g. if a symlink is not valid anymore */
+			if ((errno != ENOENT && errno != ENOTDIR) || lstat(this->full, st))
 			{
 				DBG1(DBG_LIB, "stat() on '%s' failed: %s", this->full,
 					 strerror(errno));

src/libstrongswan/utils/compat/windows.h

@@ -222,6 +222,11 @@ static inline int setenv(const char *name, const char *value, int overwrite)
 	return 0;
 }
 
+/**
+ * stat(2) behaves like lstat(2) for symbolic links on Windows
+ */
+#define lstat stat
+
 /**
  * Lazy binding, ignored on Windows
  */