diff -Naur busybox-1.13.3.orig/include/platform.h busybox-1.13.3/include/platform.h
--- busybox-1.13.3.orig/include/platform.h	2009-02-26 12:47:26.000000000 +0100
+++ busybox-1.13.3/include/platform.h	2009-05-21 17:40:57.000000000 +0200
@@ -363,3 +363,20 @@
 #endif
 
+/* TIOCGSERIAL, CBAUD and CBAUDEX are Linux specific. */
+#include <termios.h>
+#if !defined(TIOCGSERIAL)
+# if defined(__FreeBSD_kernel__)
+/*
+#  include <sys/compat/linux/linux_ioctl.h>
+#  define TIOCGSERIAL LINUX_TIOCGSERIAL
+#  define CBAUD LINUX_CBAUD
+#  define CBAUDEX LINUX_CBAUDEX
+*/
+// HACK; copied from http://svn.freebsd.org/viewvc/base/release/7.2.0/sys/compat/linux/linux_ioctl.h?view=markup
+#  define TIOCGSERIAL 0x541E
+#  define CBAUD 0x0000100f
+#  define CBAUDEX 0x00001000
+# endif
+#endif
+
 #endif	/* platform.h	*/
diff -Naur busybox-1.13.3.orig/init/init.c busybox-1.13.3/init/init.c
--- busybox-1.13.3.orig/init/init.c	2009-02-26 12:56:00.000000000 +0100
+++ busybox-1.13.3/init/init.c	2009-05-21 18:39:43.000000000 +0200
@@ -73,8 +73,10 @@
 
 #ifndef RB_HALT_SYSTEM
 	RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
+# if !defined(__FreeBSD_kernel__)
 	RB_ENABLE_CAD = 0x89abcdef,
 	RB_DISABLE_CAD = 0,
+# endif
 	RB_POWER_OFF = 0x4321fedc,
 	RB_AUTOBOOT = 0x01234567,
 #endif
@@ -244,8 +277,10 @@
 	tty.c_cc[VSTOP] = 19;	/* C-s */
 	tty.c_cc[VSUSP] = 26;	/* C-z */
 
+#if defined(__linux__)
 	/* use line discipline 0 */
 	tty.c_line = 0;
+#endif
 
 	/* Make it be sane */
 	tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
@@ -546,8 +581,10 @@
 
 	message(L_CONSOLE | L_LOG, "The system is going down NOW!");
 
+#if !defined(__FreeBSD_kernel__)
 	/* Allow Ctrl-Alt-Del to reboot system. */
 	init_reboot(RB_ENABLE_CAD);
+#endif
 
 	/* Send signals to every process _except_ pid 1 */
 	message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
@@ -817,9 +859,11 @@
 			+ (1 << SIGTSTP)
 			, stop_handler);
 
+#if !defined(__FreeBSD_kernel__)
 		/* Turn off rebooting via CTL-ALT-DEL -- we get a
 		 * SIGINT on CAD so we can shut things down gracefully... */
 		init_reboot(RB_DISABLE_CAD);
+#endif
 	}
 
 	/* Figure out where the default console should be */