patch 7.4.1770
Problem:    Cannot use true color in the terminal.
Solution:   Add the 'guicolors' option. (Nikolai Pavlov)
diff --git a/src/option.c b/src/option.c
index a5b403c..da02864 100644
--- a/src/option.c
+++ b/src/option.c
@@ -1305,7 +1305,16 @@
 			    {(char_u *)NULL, (char_u *)0L}
 #endif
 			    SCRIPTID_INIT},
-    {"guicursor",    "gcr",  P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
+    {"guicolors",   "gcol", P_BOOL|P_VI_DEF|P_VIM|P_RCLR,
+#ifdef FEAT_TERMTRUECOLOR
+			    (char_u *)&p_guicolors, PV_NONE,
+			    {(char_u *)FALSE, (char_u *)FALSE}
+#else
+			    (char_u*)NULL, PV_NONE,
+			    {(char_u *)FALSE, (char_u *)FALSE}
+#endif
+			    SCRIPTID_INIT},
+    {"guicursor",    "gcr", P_STRING|P_VI_DEF|P_ONECOMMA|P_NODUP,
 #ifdef CURSOR_SHAPE
 			    (char_u *)&p_guicursor, PV_NONE,
 			    {
@@ -3011,6 +3020,8 @@
     p_term("t_xs", T_XS)
     p_term("t_ZH", T_CZH)
     p_term("t_ZR", T_CZR)
+    p_term("t_8f", T_8F)
+    p_term("t_8b", T_8B)
 
 /* terminal key codes are not in here */
 
@@ -8353,6 +8364,17 @@
 
 #endif
 
+#ifdef FEAT_TERMTRUECOLOR
+    /* 'guicolors' */
+    else if ((int *)varp == &p_guicolors)
+    {
+# ifdef FEAT_GUI
+	if (!gui.in_use && !gui.starting)
+# endif
+	    highlight_gui_started();
+    }
+#endif
+
     /*
      * End of handling side effects for bool options.
      */