Preventing the Win32 API LoadLibrary() current directory DLL injection issue.

When loading the DLL file by the LoadLibrary() function in Windows VPN programs, we changed the behavior not to search the current directory. Based on this improvement, even if there are untrusted DLL files in the calendar directory, it is now safe to avoid the problem of unexpected security problem caused by the default loading behavior of Windows. Acknowledgments: This is based on a report by Herman Groeneveld, aka Sh4d0wman.

src/vpnclient/vpncsvc.c

@@ -143,6 +143,8 @@ void StopProcess()
 // WinMain function
 int main(int argc, char *argv[])
 {
+	InitProcessCallOnce();
+
 #ifdef	OS_WIN32
 
 	return MsService(GC_SVC_NAME_VPNCLIENT, StartProcess, StopProcess, ICO_MACHINE, argv[0]);