patch 8.1.1734: the evalfunc.c file is too big
Problem: The evalfunc.c file is too big.
Solution: Move some functions to other files.
diff --git a/src/proto/evalfunc.pro b/src/proto/evalfunc.pro
index 64a246d..afd5f63 100644
--- a/src/proto/evalfunc.pro
+++ b/src/proto/evalfunc.pro
@@ -7,6 +7,7 @@
buf_T *buflist_find_by_name(char_u *name, int curtab_only);
buf_T *tv_get_buf(typval_T *tv, int curtab_only);
buf_T *get_buf_arg(typval_T *arg);
+win_T *get_optional_window(typval_T *argvars, int idx);
void execute_redir_str(char_u *value, int value_len);
void mzscheme_call_vim(char_u *name, typval_T *args, typval_T *rettv);
float_T vim_round(float_T f);