patch 8.1.1301: when compiled with VIMDLL some messages are not shown

Problem:    When compiled with VIMDLL some messages are not shown.
Solution:   Set/reset gui.in_use and gui.starting as needed. (Ken Takata,
            closes #4361)

src/gui_w32.c

@@ -4827,6 +4827,10 @@ ole_error(char *arg)
 {
     char buf[IOSIZE];
 
+# ifdef VIMDLL
+    gui.in_use = mch_is_gui_executable();
+# endif
+
     /* Can't use emsg() here, we have not finished initialisation yet. */
     vim_snprintf(buf, IOSIZE,
 	    _("E243: Argument not supported: \"-%s\"; Use the OLE version."),

src/main.c

@@ -178,6 +178,8 @@ main
 #ifdef VIMDLL
     // Check if the current executable file is for the GUI subsystem.
     gui.starting = mch_is_gui_executable();
+#elif defined(FEAT_GUI_MSWIN)
+    gui.starting = TRUE;
 #endif
 
 #ifdef FEAT_CLIENTSERVER
@@ -3242,6 +3244,14 @@ mainerr(
     reset_signals();		/* kill us with CTRL-C here, if you like */
 #endif
 
+    // If this is a Windows GUI executable, show an error dialog box.
+#ifdef VIMDLL
+    gui.in_use = mch_is_gui_executable();
+#endif
+#ifdef FEAT_GUI_MSWIN
+    gui.starting = FALSE;   // Needed to show as error.
+#endif
+
     init_longVersion();
     mch_errmsg(longVersion);
     mch_errmsg("\n");

src/message.c

@@ -2977,7 +2977,7 @@ mch_errmsg(char *str)
     int		len;
 #endif
 
-#if (defined(UNIX) || defined(FEAT_GUI)) && (!defined(ALWAYS_USE_GUI) || !defined(VIMDLL))
+#if (defined(UNIX) || defined(FEAT_GUI)) && !defined(ALWAYS_USE_GUI) && !defined(VIMDLL)
     /* On Unix use stderr if it's a tty.
      * When not going to start the GUI also use stderr.
      * On Mac, when started from Finder, stderr is the console. */
@@ -3080,7 +3080,7 @@ mch_msg_c(char *str)
     void
 mch_msg(char *str)
 {
-#if (defined(UNIX) || defined(FEAT_GUI)) && (!defined(ALWAYS_USE_GUI) || !defined(VIMDLL))
+#if (defined(UNIX) || defined(FEAT_GUI)) && !defined(ALWAYS_USE_GUI) && !defined(VIMDLL)
     /* On Unix use stdout if we have a tty.  This allows "vim -h | more" and
      * uses mch_errmsg() when started from the desktop.
      * When not going to start the GUI also use stdout.

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1301,
 /**/
     1300,
 /**/