LLVM Minix changes

- import libcxx
 - reduce targets to the one when compiled as a tools

Change-Id: Iabb8427f80ff8e89463559a28bcb8b4f2bdbc496

usr.sbin/installboot/install_master.c

@@ -33,7 +33,7 @@ static void report(const char *label)
 	fprintf(stderr, "installboot: %s: %s\n", label, strerror(errno));
 }
 
-static void fatal(const char *label)
+static __dead void fatal(const char *label)
 {
 	report(label);
 	exit(1);