patch 8.2.2784: Vim9: cannot use \=expr in :substitute
Problem: Vim9: cannot use \=expr in :substitute.
Solution: Compile the expression into instructions and execute them when
invoked.
diff --git a/src/proto/vim9execute.pro b/src/proto/vim9execute.pro
index 2124282..46b314c 100644
--- a/src/proto/vim9execute.pro
+++ b/src/proto/vim9execute.pro
@@ -4,6 +4,7 @@
char_u *char_from_string(char_u *str, varnumber_T index);
char_u *string_slice(char_u *str, varnumber_T first, varnumber_T last, int exclusive);
int fill_partial_and_closure(partial_T *pt, ufunc_T *ufunc, ectx_T *ectx);
+char_u *exe_substitute_instr(void);
int call_def_function(ufunc_T *ufunc, int argc_arg, typval_T *argv, partial_T *partial, typval_T *rettv);
void ex_disassemble(exarg_T *eap);
int tv2bool(typval_T *tv);