LibC/Shell: set PWD env in Shell, not libc

I have no idea why I was doing it in the libc

userspace/programs/Shell/Builtin.cpp

@@ -134,21 +134,20 @@ void Builtin::initialize()
 				return 1;
 			}
 
-			BAN::StringView path;
-
-			if (arguments.size() == 1)
-			{
-				if (const char* path_env = getenv("HOME"))
-					path = path_env;
-				else
-					return 0;
-			}
+			const char* path = nullptr;
+			if (arguments.size() == 2)
+				path = arguments[1].data();
 			else
-				path = arguments[1];
+				path = getenv("HOME");
 
-			if (chdir(path.data()) == -1)
+			if (path == nullptr)
+				return 0;
+
+			if (chdir(path) == -1)
 				ERROR_RETURN("chdir", 1);
 
+			setenv("PWD", path, 1);
+
 			return 0;
 		}, true
 	));

userspace/programs/Shell/main.cpp

@@ -28,6 +28,12 @@ int main(int argc, char** argv)
 		sigaction(SIGTTOU, &sa, nullptr);
 	}
 
+	{
+		char cwd_buffer[PATH_MAX];
+		if (getcwd(cwd_buffer, sizeof(cwd_buffer)))
+			setenv("PWD", cwd_buffer, 1);
+	}
+
 	Builtin::get().initialize();
 
 	for (int i = 1; i < argc; i++)