Fix race condition allowing to run several instances of qBittorrent at the same time

src/qtsingleapp/qtsinglecoreapplication.pri

@@ -0,0 +1,10 @@
+INCLUDEPATH	+= $$PWD
+DEPENDPATH      += $$PWD
+HEADERS		+= $$PWD/qtsinglecoreapplication.h $$PWD/qtlocalpeer.h
+SOURCES		+= $$PWD/qtsinglecoreapplication.cpp $$PWD/qtlocalpeer.cpp
+
+QT *= network
+
+win32:contains(TEMPLATE, lib):contains(CONFIG, shared) {
+    DEFINES += QT_QTSINGLECOREAPPLICATION_EXPORT=__declspec(dllexport)
+}