patch 7.4.1770
Problem:    Cannot use true color in the terminal.
Solution:   Add the 'guicolors' option. (Nikolai Pavlov)
diff --git a/src/eval.c b/src/eval.c
index b82a98f..3542b77 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -14044,6 +14044,9 @@
 #ifdef FEAT_TERMRESPONSE
 	"termresponse",
 #endif
+#ifdef FEAT_TERMTRUECOLOR
+	"termtruecolor",
+#endif
 #ifdef FEAT_TEXTOBJ
 	"textobjects",
 #endif