Prevent crash when no URL is specified.

programs/winebrowser/main.c

diff --git a/programs/winebrowser/main.c b/programs/winebrowser/main.c
index 7b4f79d..1d7016d 100644
--- a/programs/winebrowser/main.c
+++ b/programs/winebrowser/main.c
@@ -51,6 +51,12 @@
   LONG r;
   wine_get_unix_file_name_t wine_get_unix_file_name_ptr;
 
+  if (argc <= 1)
+  {
+    fprintf( stderr, "Usage: winebrowser URL\n", argv[0] );
+    return 1;
+  }
+
   /* check if the argument is a local file */
   wine_get_unix_file_name_ptr = (wine_get_unix_file_name_t)
       GetProcAddress( GetModuleHandle( "KERNEL32"), "wine_get_unix_file_name");