build: change to xmake mgr.

3rd/SingleApplication-3.5.2/xmake.lua

@@ -0,0 +1,31 @@
+add_rules("mode.debug", "mode.release")
+
+target("SingleApplication")
+    add_rules("qt.static")
+    if has_config("single5") then
+        add_defines("QT_DEFAULT_MAJOR_VERSION=5")
+    else
+        add_defines("QT_DEFAULT_MAJOR_VERSION=6")
+    end
+    -- QApplication/QGuiApplication/QCoreApplication
+    add_defines("QAPPLICATION_CLASS=QApplication")
+    add_defines("QT_NO_CAST_TO_ASCII")
+    add_defines("QT_NO_CAST_FROM_ASCII")
+    add_defines("QT_NO_URL_CAST_FROM_STRING")
+    add_defines("QT_NO_CAST_FROM_BYTEARRAY")
+    add_defines("QT_USE_QSTRINGBUILDER")
+    add_defines("QT_NO_NARROWING_CONVERSIONS_IN_CONNECT")
+    add_defines("QT_NO_KEYWORDS")
+    add_defines("QT_NO_FOREACH")
+    add_includedirs(".", {public = true})
+    add_files("*.h")
+    add_files("*.cpp")
+    add_frameworks("QtCore")
+    add_frameworks("QtGui")
+    add_frameworks("QtWidgets")
+    add_frameworks("QtNetwork")
+
+option("single5")
+    set_default(false)
+    set_showmenu(true)
+    set_description("SingleApplication Build with Qt5.")