patch 8.1.1500: wrong shell command when building with VIMDLL and "!" in 'go'

Problem:    Wrong shell command when building with VIMDLL and "!" in
            'guioptions'.
Solution:   Add check for GUI in use. (Ken Takata)

Author: brammool

src/misc2.c

@@ -3253,7 +3253,11 @@ call_shell(char_u *cmd, int opt)
 
 	if (cmd == NULL || *p_sxq == NUL
 #if defined(FEAT_GUI_MSWIN) && defined(FEAT_TERMINAL)
-		|| vim_strchr(p_go, GO_TERMINAL) != NULL
+		|| (
+# ifdef VIMDLL
+		    gui.in_use &&
+# endif
+		    vim_strchr(p_go, GO_TERMINAL) != NULL)
 #endif
 		)
 	    retval = mch_call_shell(cmd, opt);

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1500,
 /**/
     1499,
 /**/