Update syncplayClient.py

Check for VC redistibutable on Windows

syncplayClient.py

@@ -14,4 +14,20 @@ except AttributeError:
 from syncplay import ep_client
 
 if __name__ == '__main__':
-    ep_client.main()
+    def isWindows():
+        return sys.platform.startswith(constants.OS_WINDOWS)
+
+    def doWindowsRedistCheck():
+        import ctypes
+        try:
+            ctypes.CDLL('vcruntime140.dll')
+        except OSError:
+            ctypes.windll.user32.MessageBoxW(0, '''Syncplay relies on the Microsoft Visual C++ Redistributable which is not installed.
+                 It can be downloaded at https://aka.ms/vs/17/release/vc_redist.x86.exe
+                 For more details see httsp://syncplay.pl/''', "Syncplay", 1)
+        sys.exit()
+
+    if isWindows():
+        doWindowsRedistCheck()
+        
+    ep_client.main()