Use default-pie and default-ssp flags in gcc

Committing only the commands for now, so that others can test the
build. TODO:
- add command explanations
- add changelog
- comment on failing tests in binutils and gcc

chapter05/gcc-pass1.xml

@@ -87,6 +87,8 @@ cd       build</userinput></screen>
     --with-sysroot=$LFS       \
     --with-newlib             \
     --without-headers         \
+    --enable-default-pie      \
+    --enable-default-ssp      \
     --disable-nls             \
     --disable-shared          \
     --disable-multilib        \

chapter06/gcc-pass2.xml

@@ -90,6 +90,8 @@ cd       build</userinput></screen>
     LDFLAGS_FOR_TARGET=-L$PWD/$LFS_TGT/libgcc      \
     --prefix=/usr                                  \
     --with-build-sysroot=$LFS                      \
+    --enable-default-pie                           \
+    --enable-default-ssp                           \
     --disable-nls                                  \
     --disable-multilib                             \
     --disable-decimal-float                        \

chapter08/gcc.xml

@@ -74,6 +74,8 @@ cd       build</userinput></screen>
 <screen><userinput remap="configure">../configure --prefix=/usr            \
              LD=ld                    \
              --enable-languages=c,c++ \
+             --enable-default-pie     \
+             --enable-default-ssp     \
              --disable-multilib       \
              --disable-bootstrap      \
              --with-system-zlib</userinput></screen>