fftw option in speex and pulseaudio

[Richard PALO <richard%netbsd.org@localhost>]

I had issues building pulseaudio with 'fftw' in my PKG_DEFAULT_OPTIONS
initially for speex...   Namely undefined fftw symbols linking with
speex.  BTW, speex performance improves considerably with both simd and
fftw options enabled.

This patch
(http://www.netbsd.org/~richard/0002-avoid-missing-symbols-with-libspeexdsp.so-when-using.patch)
resolves the symbols by linking the shared library with FFT_LIBS, but
this only gets over the missing symbol part of the problem.

Libtool marks -lfftw3 in libspeexdsp.la, but autodetection naturally
doesn't work without including the missing buildlink3 files. So in this
patch
(http://www.netbsd.org/~richard/0001-add-fftw-option-to-foil-autodetection-in-pulseaudio.patch)
I add the 'fftw' option to pulseaudio which adds the missing
dependencies as well as a bin and a couplet of
libraries to PLIST.

It'd be nice to get some feedback from NetBSD (and any other platform)
users prior to committing this.  Again, 'fftw' needs to be added to
PKG_DEFAULT_OPTIONS so that both speex and pulseaudio pick it up.

cheers