fix: make KF6 Pty build on Redox

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

local/recipes/kde/kf6-pty/source/src/kpty.cpp

@@ -439,7 +439,7 @@ void KPty::setCTty()
     setsid();
 
     // make our slave pty the new controlling terminal.
-    ioctl(d->slaveFd, TIOCSCTTY, 0);
+    ioctl(d->slaveFd, TIOCSCTTY, nullptr);
 
     // make our new process group the foreground group on the pty
     int pgrp = getpid();
@@ -448,6 +448,15 @@ void KPty::setCTty()
 
 void KPty::login(const char *user, const char *remotehost)
 {
+#ifdef __redox__
+    // Redox provides PTY allocation and terminal attributes, but it does not yet
+    // expose a utmp/wtmp database API. Keep KPty functional while making login
+    // accounting an explicit no-op on this target rather than referencing
+    // incomplete libc utmp declarations.
+    Q_UNUSED(user);
+    Q_UNUSED(remotehost);
+    return;
+#else
 #ifdef UTEMPTER_PATH
     Q_D(KPty);
 
@@ -533,10 +542,15 @@ void KPty::login(const char *user, const char *remotehost)
 #endif
 #endif
 #endif
+#endif
 }
 
 void KPty::logout()
 {
+#ifdef __redox__
+    // See KPty::login(): there is no Redox utmp/wtmp backend to update yet.
+    return;
+#else
 #ifdef UTEMPTER_PATH
     Q_D(KPty);
 
@@ -612,6 +626,7 @@ void KPty::logout()
 #endif
 #endif
 #endif
+#endif
 }
 
 bool KPty::tcGetAttr(struct ::termios *ttmode) const