setup-cygwin.bat fix:

  no parameters won't work

windows/scripts/setup-cygwin.bat

@@ -4,7 +4,7 @@ SETLOCAL
 SET CYGWINHOME=%~1\
 SET CYGWINROOT="%~1\cygwin"
 
-IF NOT "%CYGWINHOME%" == "" GOTO INIT
+IF NOT "%1" == "" GOTO INIT
 
 SET CYGWINHOME=%~dp0
 SET CYGWINROOT="%~dp0cygwin"
@@ -14,7 +14,7 @@ SET DOWNLOADPATH="%CYGWINHOME%cygwin-packages"
 SET SETUPFILE="%CYGWINHOME%setup.exe"
 SET OPTIONS=--no-shortcuts --no-startmenu --quiet-mode --no-verify
 
-IF NOT EXIST %SETUPFILE% GOTO START
+IF EXIST %SETUPFILE% GOTO START
 ECHO Missing %SETUPFILE%
 ENDLOCAL
 EXIT 1