Add noreturn attributes and remove unreachable code.

* grub-core/bus/cs5536.c (grub_cs5536_smbus_wait): Remove unreachable
	code.
	* grub-core/commands/halt.c (grub_cmd_halt): Remove unreachable
	code. Mark as noreturn.
	* grub-core/commands/minicmd.c (grub_mini_cmd_exit): Likewise.
	* grub-core/commands/reboot.c (grub_cmd_reboot): Likewise.
	* grub-core/disk/efi/efidisk.c (grub_efidisk_get_device_name): Remove
	unreachable code.
	* grub-core/kern/main.c (grub_main): Mark as noreturn.
	* grub-core/kern/rescue_reader.c (grub_rescue_run): Likewise.
	* grub-core/lib/posix_wrap/stdlib.h (abort): Likewise.
	* grub-core/normal/menu.c (run_menu): Remove unreachable code.
	* include/grub/kernel.h (grub_main): Mark as noreturn.
	* include/grub/reader.h (grub_rescue_run): Likewise.

grub-core/bus/cs5536.c

@@ -97,8 +97,6 @@ grub_cs5536_smbus_wait (grub_port_t smbbase)
       if (grub_get_time_ms () > start + 40)
 	return grub_error (GRUB_ERR_IO, "SM stalled");
     }
-
-  return GRUB_ERR_NONE;
 }
 
 grub_err_t

grub-core/commands/halt.c

@@ -24,13 +24,12 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
-static grub_err_t
+static grub_err_t __attribute__ ((noreturn))
 grub_cmd_halt (grub_command_t cmd __attribute__ ((unused)),
 	       int argc __attribute__ ((unused)),
 	       char **args __attribute__ ((unused)))
 {
   grub_halt ();
-  return 0;
 }
 
 static grub_command_t cmd;

grub-core/commands/minicmd.c

@@ -165,13 +165,13 @@ grub_mini_cmd_lsmod (struct grub_command *cmd __attribute__ ((unused)),
 }
 
 /* exit */
-static grub_err_t
+static grub_err_t __attribute__ ((noreturn))
 grub_mini_cmd_exit (struct grub_command *cmd __attribute__ ((unused)),
 		    int argc __attribute__ ((unused)),
 		    char *argv[] __attribute__ ((unused)))
 {
   grub_exit ();
-  return 0;
+  /* Not reached.  */
 }
 
 static grub_command_t cmd_cat, cmd_help;

grub-core/commands/reboot.c

@@ -24,13 +24,12 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
-static grub_err_t
+static grub_err_t __attribute__ ((noreturn))
 grub_cmd_reboot (grub_command_t cmd __attribute__ ((unused)),
 		 int argc __attribute__ ((unused)),
 		 char **args __attribute__ ((unused)))
 {
   grub_reboot ();
-  return 0;
 }
 
 static grub_command_t cmd;

grub-core/disk/efi/efidisk.c

@@ -791,6 +791,4 @@ grub_efidisk_get_device_name (grub_efi_handle_t *handle)
       grub_disk_close (parent);
       return device_name;
     }
-
-  return 0;
 }

grub-core/kern/main.c

@@ -190,7 +190,7 @@ grub_load_normal_mode (void)
 }
 
 /* The main routine.  */
-void
+void __attribute__ ((noreturn))
 grub_main (void)
 {
   /* First of all, initialize the machine.  */

grub-core/kern/rescue_reader.c

@@ -74,7 +74,7 @@ grub_rescue_read_line (char **line, int cont)
   return 0;
 }
 
-void
+void __attribute__ ((noreturn))
 grub_rescue_run (void)
 {
   grub_printf ("Entering rescue mode...\n");

grub-core/lib/posix_wrap/stdlib.h

@@ -46,7 +46,7 @@ realloc (void *ptr, grub_size_t size)
   return grub_realloc (ptr, size);
 }
 
-static inline void
+static inline void __attribute__ ((noreturn))
 abort (void)
 {
   grub_abort ();

grub-core/normal/menu.c

@@ -666,7 +666,6 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot)
     }
 
   /* Never reach here.  */
-  return -1;
 }
 
 /* Callback invoked immediately before a menu entry is executed.  */