Fix 8-color PuTTY -nw sessions broken by a recent commit

* src/term.c (init_tty): Fix the change which introduced support
for the terminfo Tc flag.  The code as installed broke colors in
PuTTY -nw sessions, because 'tigetflag' returned -1, which is
non-zero, so it was treated as the sign that true color is
supported.  But if the value returned by 'tigetflag' is -1, it means
the capability is not a boolean one, so that's not to be used as a
valid support for 24-bit color.  (Bug#44950)

diff --git a/src/term.c b/src/term.c
index d86ae12ba84d04bd36d62d804a7eb54afb719ad2..51fcef6f1ecc985ba19512a86e3dae9bed1df314 100644 (file)
--- a/src/term.c
+++ b/src/term.c
@@ -4155,7 +4155,7 @@ use the Bourne shell command 'TERM=...; export TERM' (C-shell:\n\
        /* Fall back to xterm+direct (semicolon version) if Tc is set
           (de-facto standard introduced by tmux) or if requested by
           the COLORTERM environment variable.  */
-       else if (tigetflag("Tc")
+       else if ((tigetflag("Tc") != -1)
                 || ((bg = getenv("COLORTERM")) != NULL
                     && strcasecmp(bg, "truecolor") == 0))
          {