disable ssp usage in yaboot itself

unfortunately, since we link against external libs that themselves were built
with ssp turned on, we have to provide stubs to keep the linking from failing

--- yaboot-1.3.13/Config.gentoo
+++ yaboot-1.3.13/Config.gentoo
@@ -0,0 +1,6 @@
+check_gcc=$(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null > /dev/null 2>&1; \
+	then echo "$(1)"; else echo "$(2)"; fi)
+
+CFLAGS     += $(call check_gcc, -fno-stack-protector)
+CFLAGS     += $(call check_gcc, --nopie)
+
--- yaboot-1.3.13/Makefile
+++ yaboot-1.3.13/Makefile
@@ -1,6 +1,7 @@
 ## Setup
 
 include Config
+include Config.gentoo
 
 VERSION = 1.3.13
 # Debug mode (spam/verbose)
@@ -79,7 +80,7 @@ HOSTCFLAGS = -O2 $(CFLAGS) -Wall -I/usr/
 	second/fs_of.o second/fs_ext2.o second/fs_iso.o second/fs_swap.o \
 	second/iso_util.o \
 	lib/nonstd.o \
-	lib/nosys.o lib/string.o lib/strtol.o lib/vsprintf.o lib/ctype.o lib/malloc.o lib/strstr.o
+	lib/nosys.o lib/string.o lib/strtol.o lib/vsprintf.o lib/ctype.o lib/malloc.o lib/strstr.o lib/ssp.o
 
 ifeq ($(USE_MD5_PASSWORDS),y)
 OBJS += second/md5.o
--- yaboot-1.3.14/lib/ssp.c
+++ yaboot-1.3.14/lib/ssp.c
@@ -0,0 +1,2 @@
+void __stack_chk_fail(void) {}
+void __stack_chk_fail_local(void) {}