Fix long-standing inverted signal mask in kdesktop_lock initial sigsuspend

Prevent helper thread termination signal from errantly being handled by main thread
(cherry picked from commit 37bc5cdd0e)

kdesktop/lock/lockprocess.cc

@@ -2842,6 +2842,13 @@ void ControlPipeHandlerObject::run(void) {
 	mThreadID = pthread_self();
 	mRunning = true;
 
+	sigset_t new_mask;
+	sigemptyset(&new_mask);
+	sigaddset(&new_mask, SIGUSR1);
+
+	// Unblock SIGUSR1
+	pthread_sigmask(SIG_UNBLOCK, &new_mask, NULL);
+
 	int display_number = atoi(TQString(XDisplayString(tqt_xdisplay())).replace(":","").ascii());
 
 	if (display_number < 0) {

kdesktop/lock/main.cc

@@ -378,7 +378,6 @@ int main( int argc, char **argv )
 
         if (args->isSet( "internal" )) {
             kdesktop_pid = atoi(args->getOption( "internal" ));
-            while (signalled_run == FALSE) {
             sigset_t new_mask;
             sigset_t orig_mask;
             struct sigaction act;
@@ -417,13 +416,14 @@ int main( int argc, char **argv )
             sigaction(SIGTTOU, &act, 0L);
 
             // initialize the signal masks
-                sigfillset(&new_mask);
-                sigdelset(&new_mask,SIGUSR1);
-                sigdelset(&new_mask,SIGUSR2);
-                sigdelset(&new_mask,SIGWINCH);
-                sigdelset(&new_mask,SIGTTIN);
-                sigdelset(&new_mask,SIGTTOU);
+            sigemptyset(&new_mask);
+            sigaddset(&new_mask,SIGUSR1);
+            sigaddset(&new_mask,SIGUSR2);
+            sigaddset(&new_mask,SIGWINCH);
+            sigaddset(&new_mask,SIGTTIN);
+            sigaddset(&new_mask,SIGTTOU);
 
+            while (signalled_run == FALSE) {
                 // let kdesktop know the saver process is ready
                 if (kill(kdesktop_pid, SIGTTIN) < 0) {
                     // The controlling kdesktop process probably died.  Commit suicide...
@@ -448,6 +448,9 @@ int main( int argc, char **argv )
 		// Reenable reception of X11 events on the root window
 		XSelectInput( tqt_xdisplay(), tqt_xrootwin(), rootAttr.your_event_mask );
             }
+
+	    // Block reception of all signals in this thread
+	    sigprocmask(SIG_BLOCK, &new_mask, NULL);
         }
 
         // (re)load settings here so that they actually reflect reality