FYI,
http://gitweb.dragonflybsd.org/dragonfly.git/commit/64005844ae3d5bad9607c2bdcbdf3ec627bc70bc

diff -Nur sys.orig/boot/i386/boot2/Makefile sys/boot/i386/boot2/Makefile
--- sys.orig/boot/i386/boot2/Makefile	2012-11-25 00:36:24.000000000 +0900
+++ sys/boot/i386/boot2/Makefile	2012-11-25 00:36:46.000000000 +0900
@@ -25,6 +25,8 @@
 CFLAGS=	-Os \
 	-fno-guess-branch-probability \
 	-fomit-frame-pointer \
+	-fno-unwind-tables \
+	-fno-asynchronous-unwind-tables \
 	-fno-unit-at-a-time \
 	-mno-align-long-strings \
 	-mrtd \