console-server: Enable handler iteration with -fsanitize=address

Currently when running obmc-console-server built with -fsanitize=address
we receive the following abort:

```
$ dbus-run-session ./build/obmc-console-server -i test $(realpath pts)
iniparser: cannot open etc/obmc-console.conf
3 handler types
obmc-console-server: Can't open log buffer file /var/local/log/obmc-console.log: No such file or directory
  console 'test': handler log [inactive]
=================================================================
==724703==ERROR: AddressSanitizer: global-buffer-overflow on address 0x559163200b08 at pc 0x5591631e6d08 bp 0x7ffdb2e64350 sp 0x7ffdb2e64348
READ of size 8 at 0x559163200b08 thread T0
    #0 0x5591631e6d07 in handlers_init ../console-server.c:560
    #1 0x5591631e6d07 in main ../console-server.c:1025
    #2 0x7f8e3f446249 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #3 0x7f8e3f446304 in __libc_start_main_impl ../csu/libc-start.c:360
    #4 0x5591631e7390 in _start (/home/andrew/src/openbmc.org/openbmc/obmc-console/build/obmc-console-server+0x26390)

0x559163200b08 is located 24 bytes to the left of global variable 'socket_handler' defined in '../socket-handler.c:515:34' (0x559163200b20) of size 32
0x559163200b08 is located 8 bytes to the right of global variable 'log_handler' defined in '../log-handler.c:222:34' (0x559163200ae0) of size 32
SUMMARY: AddressSanitizer: global-buffer-overflow ../console-server.c:560 in handlers_init
Shadow bytes around the buggy address:
  0x0ab2ac638110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ab2ac638120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ab2ac638130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ab2ac638140: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
  0x0ab2ac638150: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
=>0x0ab2ac638160: f9[f9]f9 f9 00 00 00 00 f9 f9 f9 f9 00 00 00 00
  0x0ab2ac638170: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ab2ac638180: 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9
  0x0ab2ac638190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ab2ac6381a0: 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
  0x0ab2ac6381b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==724703==ABORTING
```

Rework the start and stop symbol declarations to indicate we're
accessing an array, which keeps the sanitizer happy.

Change-Id: Ib17506a018702e64bbc419f0056da571847e2787
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/console-server.c b/console-server.c
index bd94fa6..d81b3b9 100644
--- a/console-server.c
+++ b/console-server.c
@@ -535,14 +535,14 @@
 static void handlers_init(struct console *console, struct config *config)
 {
 	/* NOLINTBEGIN(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
-	extern const struct handler_type *const __start_handlers;
-	extern const struct handler_type *const __stop_handlers;
+	extern const struct handler_type *const __start_handlers[];
+	extern const struct handler_type *const __stop_handlers[];
 	/* NOLINTEND(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
 	size_t n_types;
 	int j = 0;
 	size_t i;
 
-	n_types = &__stop_handlers - &__start_handlers;
+	n_types = __stop_handlers - __start_handlers;
 	console->handlers = calloc(n_types, sizeof(struct handler *));
 	if (!console->handlers) {
 		err(EXIT_FAILURE, "malloc(handlers)");
@@ -551,7 +551,7 @@
 	printf("%zu handler type%s\n", n_types, n_types == 1 ? "" : "s");
 
 	for (i = 0; i < n_types; i++) {
-		const struct handler_type *type = &__start_handlers[i];
+		const struct handler_type *type = __start_handlers[i];
 		struct handler *handler;
 
 		/* Should be picked up at build time by