patch 8.0.1685: can't set ANSI colors of a terminal window

Problem:    Can't set ANSI colors of a terminal window.
Solution:   Add term_setansicolors(), term_getansicolors() and
            g:term_ansi_colors. (Andy Massimino, closes #2747)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 1ffbb21..65279a5 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -856,6 +856,9 @@
     {"term_dumpload",	1, 2, f_term_dumpload},
     {"term_dumpwrite",	2, 3, f_term_dumpwrite},
     {"term_getaltscreen", 1, 1, f_term_getaltscreen},
+# if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
+    {"term_getansicolors", 1, 1, f_term_getansicolors},
+# endif
     {"term_getattr",	2, 2, f_term_getattr},
     {"term_getcursor",	1, 1, f_term_getcursor},
     {"term_getjob",	1, 1, f_term_getjob},
@@ -868,6 +871,9 @@
     {"term_list",	0, 0, f_term_list},
     {"term_scrape",	2, 2, f_term_scrape},
     {"term_sendkeys",	2, 2, f_term_sendkeys},
+# if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
+    {"term_setansicolors", 2, 2, f_term_setansicolors},
+# endif
     {"term_setkill",	2, 2, f_term_setkill},
     {"term_setrestore",	2, 2, f_term_setrestore},
     {"term_start",	1, 2, f_term_start},