Use safer allocation macros

Use of these macros, apart from the benefits mentioned in the commit
that adds the macros, has some other good side effects:

-  Consistency in getting the size of the object from sizeof(type),
   instead of a mix of sizeof(type) sometimes and sizeof(*p) other
   times.

-  More readable code: no casts, and no sizeof(), so also shorter lines
   that we don't need to cut.

-  Consistency in using array allocation calls for allocations of arrays
   of objects, even when the object size is 1.

Cc: Valentin V. Bartenev <vbartenev@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/nss.c

@@ -6,6 +6,8 @@
 #include <strings.h>
 #include <ctype.h>
 #include <stdatomic.h>
+
+#include "alloc.h"
 #include "prototypes.h"
 #include "../libsubid/subid.h"
 #include "shadowlog_internal.h"
@@ -100,7 +102,7 @@ void nss_init(const char *nsswitch_path) {
 				subid_nss = NULL;
 				goto done;
 			}
-			subid_nss = malloc(sizeof(*subid_nss));
+			subid_nss = MALLOC(struct subid_nss_ops);
 			if (!subid_nss) {
 				dlclose(h);
 				goto done;