Add fallback for 24-bit terminal color via COLORTERM=truecolor

* src/term.c (init_tty): When COLORTERM=truecolor is defined,
override setaf/setab/colors terminfo capabilities with 24-bit
color support.

* doc/misc/efaq.texi (Colors on a TTY): Mention the possibility to
enable 24-bit color via the COLORTERM environment variable.

(Bug#41846)

Copyright-paperwork-exempt: yes

1 files changed, 4 insertions, 0 deletions

diff --git a/doc/misc/efaq.texi b/doc/misc/efaq.texi
index f5f01848f77..8f7ed715b52 100644
--- a/doc/misc/efaq.texi
+++ b/doc/misc/efaq.texi
@@ -1595,6 +1595,10 @@ xterm-direct2   xterm with direct-color indexing (old)
 xterm-direct    xterm with direct-color indexing
 @end example
 
+If Terminfo database is not available, but 24-bit direct color mode is
+supported, it can still be enabled by defining the environment
+variable @env{COLORTERM} to @samp{truecolor}.
+
 Terminals with @samp{RGB} capability treat pixels #000001 - #000007 as
 indexed colors to maintain backward compatibility with applications
 that are unaware of direct color mode.  Therefore the seven darkest