Build fails with ruby 1.9

When ruby 1.9 is used or when ruby 1.8 AND ruby 1.9 are installed, the build fails.
A patch is attached to use ruby 1.8. It must be used AFTER the one proposed in bug #5628

[ 97%] Building CXX object bindings/qpid/ruby/CMakeFiles/cqpid_ruby.dir/rubyRUBY_wrap.cxx.o
cd /home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby && /usr/bin/c++ -Dcqpid_ruby_EXPORTS -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wno-error=cast-qual -Wno-error=cast-align -D_FORTIFY_SOURCE=2 -O2 -g -DNDEBUG -fPIC -I/usr/include/ruby-1.9.1 -I/usr/include/ruby-1.9.1/x86_64-linux -I/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/include -I/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/bindings -fno-strict-aliasing -o CMakeFiles/cqpid_ruby.dir/rubyRUBY_wrap.cxx.o -c /home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx: In function ‘VALUE VariantToRb(const qpid::types::Variant*)’:
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2237:38: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(error, ex.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx: In function ‘VALUE wrap_new_Address_SWIG_0(int, VALUE*, VALUE)’:
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2307:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2311:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2315:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2319:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2323:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2327:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2331:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2335:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^
/home/sebastien/devel/admin-repository/qpid-cpp/qpid-cpp-0.26/obj-x86_64-linux-gnu/bindings/qpid/ruby/rubyRUBY_wrap.cxx:2339:36: error: format not a string literal and no format arguments [-Werror=format-security]
rb_raise(merror, error.what());
^