Try fixing linking again

Before 1.7.5, we were setting -fno-exceptions etc on CXXFLAGS. In 1.7.6
we set it as CPPFLAGS. Try fixing. Also, I'm fairly sure it's safe to
set these unconditionally.

Fixes https://github.com/harfbuzz/harfbuzz/issues/880 (or so I hope)
2 files changed