sddm: stub sddm-helper utmp/utmpx login accounting for Redox

src/helper/HelperApp.cpp includes <utmpx.h> and writes utmpx login/logout
records (setutxent/pututxline/updwtmpx). Redox has no utmp/utmpx login-accounting
database -> "fatal error: utmpx.h: No such file". Guard the include and the
utmpLogin/utmpLogout bodies under __redox__ as no-ops (login records are not
tracked on Redox). The sddm daemon already links; this unblocks sddm-helper.

local/recipes/kde/sddm/recipe.toml

@@ -13,6 +13,9 @@ patches = [
     # Redox has no Linux/FreeBSD VT subsystem (VT_ACTIVATE/VT_WAITACTIVE/KDSETMODE
     # etc.); stub SDDM::VirtualTerminal to no-ops (greeter runs on the compositor).
     "redox-virtualterminal-stub.patch",
+    # Redox has no utmp/utmpx login-accounting DB; stub sddm-helper's
+    # utmpLogin/utmpLogout to no-ops (skip <utmpx.h>).
+    "redox-helper-utmpx-stub.patch",
 ]
 
 [build]

local/recipes/kde/sddm/redox-helper-utmpx-stub.patch

@@ -0,0 +1,46 @@
+--- a/src/helper/HelperApp.cpp
++++ b/src/helper/HelperApp.cpp
+@@ -41,7 +41,9 @@
+ #if defined(Q_OS_LINUX)
+ #include <utmp.h>
+ #endif
++#if !defined(__redox__)
+ #include <utmpx.h>
++#endif
+ #include <QByteArray>
+ #include <signal.h>
+ 
+@@ -301,6 +303,10 @@
+     }
+ 
+     void HelperApp::utmpLogin(const QString &vt, const QString &displayName, const QString &user, qint64 pid, bool authSuccessful) {
++#if defined(__redox__)
++        // Redox has no utmp/utmpx login-accounting database; no-op.
++        Q_UNUSED(vt); Q_UNUSED(displayName); Q_UNUSED(user); Q_UNUSED(pid); Q_UNUSED(authSuccessful);
++#else
+         struct utmpx entry { };
+         struct timeval tv;
+ 
+@@ -339,9 +345,14 @@
+ #if defined(Q_OS_LINUX)
+         updwtmpx(authSuccessful ? "/var/log/wtmp" : "/var/log/btmp", &entry);
+ #endif
++#endif // !__redox__
+     }
+ 
+     void HelperApp::utmpLogout(const QString &vt, const QString &displayName, qint64 pid) {
++#if defined(__redox__)
++        // Redox has no utmp/utmpx login-accounting database; no-op.
++        Q_UNUSED(vt); Q_UNUSED(displayName); Q_UNUSED(pid);
++#else
+         struct utmpx entry { };
+         struct timeval tv;
+ 
+@@ -378,6 +389,7 @@
+ #elif defined(Q_OS_FREEBSD)
+         pututxline(&entry);
+ #endif
++#endif // !__redox__
+     }
+ }
+