patch 8.1.0785: depending on the configuration some functions are unused

Problem:    Depending on the configuration some functions are unused.
Solution:   Add more #ifdefs, remove unused functions. (Dominique Pelle,
            closes #3822)
diff --git a/src/userfunc.c b/src/userfunc.c
index 49c34c1..6887c2c 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -2560,6 +2560,7 @@
     return n;
 }
 
+#if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) || defined(PROTO)
     char_u *
 get_expanded_name(char_u *name, int check)
 {
@@ -2575,6 +2576,7 @@
     vim_free(p);
     return NULL;
 }
+#endif
 
 #if defined(FEAT_PROFILE) || defined(PROTO)
 /*