patch 9.1.0742: getcmdprompt() implementation can be improved

Problem:  getcmdprompt() implementation can be improved
Solution: Improve and simplify it (h-east)

closes: #15743

Signed-off-by: h-east <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 61f8379..ef7ca91 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -30,7 +30,6 @@
 
 #ifdef FEAT_EVAL
 static int	new_cmdpos;	// position set by set_cmdline_pos()
-static char_u	current_prompt[CMDBUFFSIZE + 1] = "";
 #endif
 
 static int	extra_char = NUL;  // extra character to display when redrawing
@@ -50,9 +49,6 @@
 static void	draw_cmdline(int start, int len);
 static void	save_cmdline(cmdline_info_T *ccp);
 static void	restore_cmdline(cmdline_info_T *ccp);
-#ifdef FEAT_EVAL
-static char_u	*get_prompt(void);
-#endif
 static int	cmdline_paste(int regname, int literally, int remcr);
 static void	redrawcmdprompt(void);
 static int	ccheck_abbr(int);
@@ -4236,24 +4232,6 @@
 }
 
 /*
- * Get current command line prompt.
- */
-    static char_u *
-get_prompt(void)
-{
-    return current_prompt;
-}
-
-/*
- * Set current command line prompt.
- */
-    void
-set_prompt(char_u* str)
-{
-    vim_strncpy(current_prompt, str, sizeof(current_prompt) - 1);
-}
-
-/*
  * "getcmdpos()" function
  */
     void
@@ -4272,7 +4250,8 @@
 {
     cmdline_info_T *p = get_ccline_ptr();
     rettv->v_type = VAR_STRING;
-    rettv->vval.v_string = p != NULL ? vim_strsave(get_prompt()) : NULL;
+    rettv->vval.v_string = p != NULL && p->cmdprompt != NULL ?
+					    vim_strsave(p->cmdprompt) : NULL;
 }
 
 /*
@@ -4898,8 +4877,6 @@
     cmd_silent = FALSE;		// Want to see the prompt.
     if (prompt != NULL)
     {
-	set_prompt(prompt);
-
 	// Only the part of the message after the last NL is considered as
 	// prompt for the command line
 	p = vim_strrchr(prompt, '\n');