patch 8.2.4883: string interpolation only works in heredoc
Problem: String interpolation only works in heredoc.
Solution: Support interpolated strings. Use syntax for heredoc consistent
with strings, similar to C#. (closes #10327)
diff --git a/src/proto/evalvars.pro b/src/proto/evalvars.pro
index ab4320d..97bec7d 100644
--- a/src/proto/evalvars.pro
+++ b/src/proto/evalvars.pro
@@ -105,4 +105,6 @@
void copy_callback(callback_T *dest, callback_T *src);
void expand_autload_callback(callback_T *cb);
void free_callback(callback_T *callback);
+char_u *eval_all_expr_in_str(char_u *str);
+
/* vim: set ft=c : */