get rid of non-ANSI function declarations missing (void)

Detected by Smatch

include/osmocom/core/backtrace.h

@@ -1,6 +1,6 @@
 #ifndef _OSMO_BACKTRACE_H_
 #define _OSMO_BACKTRACE_H_
 
-void osmo_generate_backtrace();
+void osmo_generate_backtrace(void);
 
 #endif

include/osmocom/vty/command.h

@@ -316,7 +316,7 @@ void install_node(struct cmd_node *, int (*)(struct vty *));
 void install_default(enum node_type);
 void install_element(enum node_type, struct cmd_element *);
 void install_element_ve(struct cmd_element *cmd);
-void sort_node();
+void sort_node(void);
 
 /* Concatenates argv[shift] through argv[argc-1] into a single NUL-terminated
    string with a space between each element (allocated using

src/backtrace.c

@@ -29,7 +29,7 @@
 
 #ifdef HAVE_EXECINFO_H
 #include <execinfo.h>
-void osmo_generate_backtrace()
+void osmo_generate_backtrace(void)
 {
 	int i, nptrs;
 	void *buffer[100];

src/vty/command.c

@@ -152,7 +152,7 @@ static int is_config(struct vty *vty)
 }
 
 /* Sort each node's command element according to command string. */
-void sort_node()
+void sort_node(void)
 {
 	unsigned int i, j;
 	struct cmd_node *cnode;

src/vty/vty.c

@@ -45,7 +45,7 @@ static void vty_clear_buf(struct vty *vty)
 }
 
 /* Allocate new vty struct. */
-struct vty *vty_new()
+struct vty *vty_new(void)
 {
 	struct vty *new = talloc_zero(tall_vty_ctx, struct vty);
 
@@ -1591,7 +1591,7 @@ struct cmd_node vty_node = {
 };
 
 /* Reset all VTY status. */
-void vty_reset()
+void vty_reset(void)
 {
 	unsigned int i;
 	struct vty *vty;
@@ -1631,7 +1631,7 @@ static void vty_save_cwd(void)
 	strcpy(vty_cwd, cwd);
 }
 
-char *vty_get_cwd()
+char *vty_get_cwd(void)
 {
 	return vty_cwd;
 }
@@ -1641,7 +1641,7 @@ int vty_shell_serv(struct vty *vty)
 	return vty->type == VTY_SHELL_SERV ? 1 : 0;
 }
 
-void vty_init_vtysh()
+void vty_init_vtysh(void)
 {
 	vtyvec = vector_init(VECTOR_MIN_SIZE);
 }