bonnie++ was not compiled using the TARGET_CXXFLAGS we passed, which will result
in build failures on e.g: ARM VFP toolchains, fix that.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/packages@39798 3c298f89-4303-0410-b956-a3cf2f4a3e73