doc: Mention setting build flag vars in local.mk

Prepare for 1.4.12 release

Prepare for 1.4.11 release

I forgot to install the contrib/morse/* scripts in 1.4.10,
so 1.4.11 fixes that.

NEWS.md: Update with documentation improvements

beep-1.4.9 release

beep-1.4.8 release

beep-1.4.7 release

beep-1.4.6 release

beep-1.4.4 release

beep-1.4.3

Stop compiling with `-fcf-protection` in `CFLAGS_gcc` if the platform
does not support it (such as the Raspberry Pi ARMs).