Changes for Drawpile Client to run on Debian stable

drawpile.diff

diff --git a/src/client/canvas/aclfilter.cpp b/src/client/canvas/aclfilter.cpp
index 92580a5f..a808bacc 100644
--- a/src/client/canvas/aclfilter.cpp
+++ b/src/client/canvas/aclfilter.cpp
@@ -27,6 +27,10 @@
 #include "../shared/net/annotation.h"
 #include "../shared/net/undo.h"
 
+#ifndef Q_FALLTHROUGH
+#define Q_FALLTHROUGH() (void)0
+#endif
+
 namespace canvas {
 
 AclFilter::AclFilter(QObject *parent)
diff --git a/src/client/ora/orawriter.cpp b/src/client/ora/orawriter.cpp
index 933352b2..0193c2a9 100644
--- a/src/client/ora/orawriter.cpp
+++ b/src/client/ora/orawriter.cpp
@@ -41,7 +41,7 @@ static bool putPngInZip(KZip &zip, const QString &filename, const QImage &image,
 	zip.setCompression(KZip::NoCompression);
 	if(!zip.writeFile(filename, buf.data())) {
 		if(errorMessage)
-			*errorMessage = zip.errorString();
+			*errorMessage = QString("ZIP error");
 		return false;
 	}
 	return true;
@@ -145,7 +145,7 @@ static bool writeStackXml(KZip &zip, const paintcore::LayerStack *image, const Q
 	zip.setCompression(KZip::DeflateCompression);
 	if(!zip.writeFile("stack.xml", buffer.data())) {
 		if(errorMessage)
-			*errorMessage = zip.errorString();
+			*errorMessage = QString("ZIP error");
 		return false;
 	}
 	return true;
@@ -204,7 +204,7 @@ bool saveOpenRaster(const QString& filename, const paintcore::LayerStack *image,
 	KZip zf(filename);
 	if(!zf.open(QIODevice::WriteOnly)) {
 		if(errorMessage)
-			*errorMessage = zf.errorString();
+			*errorMessage = QString("ZIP error");
 		return false;
 	}
 
@@ -213,7 +213,7 @@ bool saveOpenRaster(const QString& filename, const paintcore::LayerStack *image,
 	zf.setCompression(KZip::NoCompression);
 	if(!zf.writeFile("mimetype", QByteArray("image/openraster"))) {
 		if(errorMessage)
-			*errorMessage = zf.errorString();
+			*errorMessage = QString("ZIP error");
 		return false;
 	}
 
@@ -237,7 +237,7 @@ bool saveOpenRaster(const QString& filename, const paintcore::LayerStack *image,
 
 	if(!zf.close()) {
 		if(errorMessage)
-			*errorMessage = zf.errorString();
+			*errorMessage = QString("ZIP error");
 		return false;
 	}
 	return true;
diff --git a/src/desktop/docks/navigator.cpp b/src/desktop/docks/navigator.cpp
index 024c53cb..0a1e5bf1 100644
--- a/src/desktop/docks/navigator.cpp
+++ b/src/desktop/docks/navigator.cpp
@@ -160,7 +160,7 @@ void NavigatorView::paintEvent(QPaintEvent *)
 	if(qAbs(m_focusRect[0].y() - m_focusRect[1].y()) >= 1.0 || m_focusRect[0].x() > m_focusRect[1].x()) {
 		const QLineF right { m_focusRect[1], m_focusRect[2] };
 		const QLineF unitVector = right.unitVector().translated(-right.p1());
-		QLineF normal = unitVector.normalVector().translated(right.center());
+		QLineF normal = unitVector.normalVector().translated(0.5 * right.p1() + 0.5 * right.p2());
 		normal.setLength(10 / scale);
 		painter.drawLine(normal);
 	}
diff --git a/src/shared/server/loginhandler.cpp b/src/shared/server/loginhandler.cpp
index ae84c11d..4bfd88cb 100644
--- a/src/shared/server/loginhandler.cpp
+++ b/src/shared/server/loginhandler.cpp
@@ -36,6 +36,10 @@
 #include <QNetworkRequest>
 #include <QNetworkReply>
 
+#ifndef Q_FALLTHROUGH
+#define Q_FALLTHROUGH() (void)0
+#endif
+
 namespace server {
 
 LoginHandler::LoginHandler(Client *client, SessionServer *server) :