patch 8.2.3751: cannot assign a lambda to an option that takes a function

Problem:    Cannot assign a lambda to an option that takes a function.
Solution:   Automatically convert the lambda to a string. (Yegappan
            Lakshmanan, closes #9286)
diff --git a/src/if_ruby.c b/src/if_ruby.c
index 5098468..0d7eaf2 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -875,7 +875,7 @@
     char_u *sval;
     rb_encoding *enc;
 
-    if (get_option_value((char_u *)"enc", &lval, &sval, 0) == gov_string)
+    if (get_option_value((char_u *)"enc", &lval, &sval, NULL, 0) == gov_string)
     {
 	enc = rb_enc_find((char *)sval);
 	vim_free(sval);
@@ -895,7 +895,7 @@
     rb_encoding *enc;
     VALUE v;
 
-    if (get_option_value((char_u *)"enc", &lval, &sval, 0) == gov_string)
+    if (get_option_value((char_u *)"enc", &lval, &sval, NULL, 0) == gov_string)
     {
 	enc = rb_enc_find((char *)sval);
 	vim_free(sval);