patch 8.2.1491: Vim9: crash when compiling heredoc lines start with comment

Problem:    Vim9: crash when compiling heredoc lines start with comment.
Solution:   Skip over NULL pointers. Do not remove comment and empty lines
            when fetching function lines. (closes #6743)
diff --git a/src/proto/scriptfile.pro b/src/proto/scriptfile.pro
index 00f1301..52df2ca 100644
--- a/src/proto/scriptfile.pro
+++ b/src/proto/scriptfile.pro
@@ -29,13 +29,13 @@
 char_u *get_scriptname(scid_T id);
 void free_scriptnames(void);
 void free_autoload_scriptnames(void);
-linenr_T get_sourced_lnum(char_u *(*fgetline)(int, void *, int, int), void *cookie);
-char_u *getsourceline(int c, void *cookie, int indent, int do_concat);
+linenr_T get_sourced_lnum(char_u *(*fgetline)(int, void *, int, getline_opt_T), void *cookie);
+char_u *getsourceline(int c, void *cookie, int indent, getline_opt_T options);
 void ex_scriptencoding(exarg_T *eap);
 void ex_scriptversion(exarg_T *eap);
 void ex_finish(exarg_T *eap);
 void do_finish(exarg_T *eap, int reanimate);
-int source_finished(char_u *(*fgetline)(int, void *, int, int), void *cookie);
+int source_finished(char_u *(*fgetline)(int, void *, int, getline_opt_T), void *cookie);
 char_u *autoload_name(char_u *name);
 int script_autoload(char_u *name, int reload);
 /* vim: set ft=c : */