patch 8.2.0816: terminal test fails when compiled with Athena

Problem:    Terminal test fails when compiled with Athena.
Solution:   Do give an error when the GUI is not running. (hint by Dominique
            Pelle, closes #5928, closes #6132)
diff --git a/src/channel.c b/src/channel.c
index 68adbc3..2b85ec9 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -5308,6 +5308,7 @@
 		{
 		    char_u	*color_name;
 		    guicolor_T	guicolor;
+		    int		called_emsg_before = called_emsg;
 
 		    color_name = tv_get_string_chk(&li->li_tv);
 		    if (color_name == NULL)
@@ -5315,7 +5316,12 @@
 
 		    guicolor = GUI_GET_COLOR(color_name);
 		    if (guicolor == INVALCOLOR)
+		    {
+			if (called_emsg_before == called_emsg)
+			    // may not get the error if the GUI didn't start
+			    semsg(_(e_alloc_color), color_name);
 			return FAIL;
+		    }
 
 		    rgb[n] = GUI_MCH_GET_RGB(guicolor);
 		}
diff --git a/src/globals.h b/src/globals.h
index 60c3c66..648da7d 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1767,6 +1767,9 @@
 
 EXTERN char e_lock_unlock[]	INIT(= N_("E940: Cannot lock or unlock variable %s"));
 #endif
+#if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
+EXTERN char e_alloc_color[]	INIT(= N_("E254: Cannot allocate color %s"));
+#endif
 
 #ifdef FEAT_GUI_MAC
 EXTERN short disallow_gui	INIT(= FALSE);
diff --git a/src/gui.c b/src/gui.c
index 13b65cb..93b8bb6 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -4741,7 +4741,7 @@
 	    && gui.in_use
 #endif
 	    )
-	semsg(_("E254: Cannot allocate color %s"), name);
+	semsg(_(e_alloc_color), name);
     return t;
 }
 
diff --git a/src/term.c b/src/term.c
index e79fa5e..5880589 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1381,7 +1381,7 @@
     t = termgui_mch_get_color(name);
 
     if (t == INVALCOLOR)
-	semsg(_("E254: Cannot allocate color %s"), name);
+	semsg(_(e_alloc_color), name);
     return t;
 }
 
@@ -1587,9 +1587,9 @@
 
 	    log_tr("Received t_Co, redraw_asap(): %d", r);
 	}
-#else
+# else
 	redraw_asap(CLEAR);
-#endif
+# endif
     }
 }
 #endif
@@ -1597,10 +1597,10 @@
 #ifdef HAVE_TGETENT
 static char *(key_names[]) =
 {
-#ifdef FEAT_TERMRESPONSE
+# ifdef FEAT_TERMRESPONSE
     // Do this one first, it may cause a screen redraw.
     "Co",
-#endif
+# endif
     "ku", "kd", "kr", "kl",
     "#2", "#4", "%i", "*7",
     "k1", "k2", "k3", "k4", "k5", "k6",
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index bb9cdc7..a8a549c 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -1009,13 +1009,17 @@
   call assert_fails(cmd, 'E475:')
   let cmd = "call term_start('', {'term_highlight' : []})"
   call assert_fails(cmd, 'E475:')
-  if has('gui')
+  if has('gui') || has('termguicolors')
     let cmd = "call term_start('', {'ansi_colors' : 'abc'})"
     call assert_fails(cmd, 'E475:')
     let cmd = "call term_start('', {'ansi_colors' : [[]]})"
     call assert_fails(cmd, 'E730:')
     let cmd = "call term_start('', {'ansi_colors' : repeat(['blue'], 18)})"
-    call assert_fails(cmd, 'E475:')
+    if has('gui_running') || has('termguicolors')
+      call assert_fails(cmd, 'E475:')
+    else
+      call assert_fails(cmd, 'E254:')
+    endif
   endif
 endfunc
 
@@ -2668,7 +2672,6 @@
 " Test for passing invalid arguments to terminal functions
 func Test_term_func_invalid_arg()
   call assert_fails('let b = term_getaltscreen([])', 'E745:')
-  call assert_fails('let p = term_getansicolors([])', 'E745:')
   call assert_fails('let a = term_getattr(1, [])', 'E730:')
   call assert_fails('let c = term_getcursor([])', 'E745:')
   call assert_fails('let l = term_getline([], 1)', 'E745:')
@@ -2677,10 +2680,13 @@
   call assert_fails('let s = term_getstatus([])', 'E745:')
   call assert_fails('let s = term_scrape([], 1)', 'E745:')
   call assert_fails('call term_sendkeys([], "a")', 'E745:')
-  call assert_fails('call term_setansicolors([], [])', 'E745:')
   call assert_fails('call term_setapi([], "")', 'E745:')
   call assert_fails('call term_setrestore([], "")', 'E745:')
   call assert_fails('call term_setkill([], "")', 'E745:')
+  if has('gui') || has('termguicolors')
+    call assert_fails('let p = term_getansicolors([])', 'E745:')
+    call assert_fails('call term_setansicolors([], [])', 'E745:')
+  endif
 endfunc
 
 " Test for sending various special keycodes to a terminal
diff --git a/src/version.c b/src/version.c
index 543f5a8..f2afc0b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    816,
+/**/
     815,
 /**/
     814,