Don't crash during a slow (>= 60 seconds) startup on X11

The upstream bug report: QTBUG-58709.

A quick benchmark shows that the added QCoreApplication::processEvents()
call takes the same time in Debug and Release builds of YACReader and
YACReaderLibrary - from 0.5 to 0.6 milliseconds. 0.6 milliseconds is not
a noticeable startup slowdown, especially considering that the event
loop does useful work: processes events, which would have to be handled
eventually anyway.

I haven't restricted the workaround to Linux/X11: no need to introduce
a potential behavior difference between supported platforms.

The same workaround can be applied to YACReaderLibraryServer, but I
don't use the server and cannot test it.

Author: vedgy

YACReader/main.cpp

@@ -98,6 +98,11 @@ int main(int argc, char *argv[])
 #else
     QApplication app(argc, argv);
 #endif
+    // Prevent SIGPIPE, then "ICE default IO error handler doing an exit(), pid = <PID>, errno = 32"
+    // crash on X11 when the first event loop starts at least 60 seconds after a Qt application
+    // launch. This can happen during a Debug launch of YACReader from Qt Creator if Qt debug
+    // symbols are installed in the system or a breakpoint is hit before any event loop is entered.
+    QCoreApplication::processEvents();
 
 #ifdef FORCE_ANGLE
     app.setAttribute(Qt::AA_UseOpenGLES);

YACReaderLibrary/main.cpp

@@ -120,6 +120,11 @@ int main(int argc, char **argv)
 {
     qInstallMessageHandler(messageHandler);
     QApplication app(argc, argv);
+    // Prevent SIGPIPE, then "ICE default IO error handler doing an exit(), pid = <PID>, errno = 32"
+    // crash on X11 when the first event loop starts at least 60 seconds after a Qt application
+    // launch. This can happen during a Debug launch of YACReaderLibrary from Qt Creator if a
+    // breakpoint is hit before any event loop is entered.
+    QCoreApplication::processEvents();
 
 #ifdef FORCE_ANGLE
     app.setAttribute(Qt::AA_UseOpenGLES);