patch 8.2.4202: Vim9: cannot export function that exists globally

Problem:    Vim9: cannot export function that exists globally.
Solution:   When checking if a function already exists only check for
            script-local functions. (closes #9615)
diff --git a/src/vim.h b/src/vim.h
index f418e04..9aac6d3 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2798,4 +2798,8 @@
 #define VSE_SHELL	1	// escape for a shell command
 #define VSE_BUFFER	2	// escape for a ":buffer" command
 
+// Flags used by find_func_even_dead()
+#define FFED_IS_GLOBAL	1	// "g:" was used
+#define FFED_NO_GLOBAL	2	// only check for script-local functions
+
 #endif // VIM__H