zpool: import: use realloc for realloc, remove strtok

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12094

cmd/zpool/zpool_util.c

@@ -49,6 +49,22 @@ safe_malloc(size_t size)
 	return (data);
 }
 
+/*
+ * Utility function to guarantee realloc() success.
+ */
+void *
+safe_realloc(void *from, size_t size)
+{
+	void *data;
+
+	if ((data = realloc(from, size)) == NULL) {
+		(void) fprintf(stderr, "internal error: out of memory\n");
+		exit(1);
+	}
+
+	return (data);
+}
+
 /*
  * Display an out of memory error message and abort the current program.
  */