emacs-27 c006061: A better fix for bug#43886

[Eli Zaretskii]

branch: emacs-27
commit c00606171f88be0df2c19346fa53f401ea71c71f
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    A better fix for bug#43886
    
    * src/xfaces.c (load_color2, Fcolor_distance): Revert last change.
    * src/term.c (clear_tty_hooks): Don't clear defined_color_hook.
---
 src/term.c   |  4 +++-
 src/xfaces.c | 10 ----------
 2 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/src/term.c b/src/term.c
index 94bf013..370f6fc 100644
--- a/src/term.c
+++ b/src/term.c
@@ -3842,7 +3842,9 @@ clear_tty_hooks (struct terminal *terminal)
   terminal->update_begin_hook = 0;
   terminal->update_end_hook = 0;
   terminal->set_terminal_window_hook = 0;
-  terminal->defined_color_hook = 0;
+  /* Don't clear the defined_color_hook, as that makes it impossible
+     to unload or load a theme when some TTY frame is suspended.  */
+  /* terminal->defined_color_hook = 0; */
   terminal->mouse_position_hook = 0;
   terminal->frame_rehighlight_hook = 0;
   terminal->frame_raise_lower_hook = 0;
diff --git a/src/xfaces.c b/src/xfaces.c
index fab29ef..66d6c34 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -1059,13 +1059,6 @@ static unsigned long
 load_color2 (struct frame *f, struct face *face, Lisp_Object name,
              enum lface_attribute_index target_index, Emacs_Color *color)
 {
-  if (FRAME_TERMINAL (f)->defined_color_hook == NULL)
-    {
-      Lisp_Object frame;
-      XSETFRAME (frame, f);
-      signal_error ("Unable to load colors for suspended TTY frame", frame);
-    }
-
   eassert (STRINGP (name));
   eassert (target_index == LFACE_FOREGROUND_INDEX
           || target_index == LFACE_BACKGROUND_INDEX
@@ -4398,9 +4391,6 @@ two lists of the form (RED GREEN BLUE) aforementioned. */)
   struct frame *f = decode_live_frame (frame);
   Emacs_Color cdef1, cdef2;
 
-  if (FRAME_TERMINAL (f)->defined_color_hook == NULL)
-    signal_error ("Unable to validate colors for suspended TTY frame", frame);
-
   if (!(CONSP (color1) && parse_rgb_list (color1, &cdef1))
       && !(STRINGP (color1)
            && FRAME_TERMINAL (f)->defined_color_hook (f,