hostid: do not output sign-extended host id. Closes 6056

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/hostid.c b/coreutils/hostid.c
index 5c1a4e0..e5b1f51 100644
--- a/coreutils/hostid.c
+++ b/coreutils/hostid.c
@@ -36,7 +36,8 @@
 		bb_show_usage();
 	}
 
-	printf("%08lx\n", gethostid());
+	/* POSIX says gethostid returns a "32-bit identifier" */
+	printf("%08x\n", (unsigned)(uint32_t)gethostid());
 
 	return fflush_all();
 }