cli: drop _NMC_RL_STARTUPHOOK_ARGS

Fixes incompatible pointer types warning, which became an error in
newer compilers (e.g., https://bugs.gentoo.org/938249).

Modern libedit versions use the same type signature as readline for
rl_startup_hook, both declare

typedef int	 rl_hook_func_t(void)

This essentially reverts f47d55fc66 ("cli: Fix for rl_startup_hook
function signatures mismatch (-lreadline vs -ledit)").

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/2082

src/nmcli/agent.c

@@ -57,7 +57,7 @@ usage_agent_all(void)
 static char *pre_input_deftext;
 
 static int
-set_deftext(_NMC_RL_STARTUPHOOK_ARGS)
+set_deftext(void)
 {
     if (pre_input_deftext && rl_startup_hook) {
         rl_insert_text(pre_input_deftext);

src/nmcli/common.c

@@ -1138,7 +1138,7 @@ nmc_rl_gen_func_ifnames(const char *text, int state)
 char *nmc_rl_pre_input_deftext;
 
 int
-nmc_rl_set_deftext(_NMC_RL_STARTUPHOOK_ARGS)
+nmc_rl_set_deftext(void)
 {
     if (nmc_rl_pre_input_deftext && rl_startup_hook) {
         rl_insert_text(nmc_rl_pre_input_deftext);

src/nmcli/common.h

@@ -50,17 +50,9 @@ char            *nmc_rl_gen_func_ifnames(const char *text, int state);
 gboolean         nmc_get_in_readline(void);
 void             nmc_set_in_readline(gboolean in_readline);
 
-#if HAVE_EDITLINE_READLINE
-/* libedit has different signature for rl_startup_hook function */
-#define _NMC_RL_STARTUPHOOK_ARGS const char *c, int i
-#else
-/* By default the libreadline shall be used */
-#define _NMC_RL_STARTUPHOOK_ARGS void
-#endif
-
 /* for pre-filling a string to readline prompt */
 extern char *nmc_rl_pre_input_deftext;
-int          nmc_rl_set_deftext(_NMC_RL_STARTUPHOOK_ARGS);
+int          nmc_rl_set_deftext(void);
 
 char *nmc_parse_lldp_capabilities(guint value);