Add SLEEF to README. I was going to add it to the CI, but it looks as if Ubuntu's libsleef-dev doesn't include sleefdft.

.build.yml

@@ -4,6 +4,7 @@ packages:
   - libsamplerate0-dev
   - libsndfile1-dev
   - libfftw3-dev
+#  - libsleef-dev
   - ladspa-sdk
   - lv2-dev
   - vamp-plugin-sdk
@@ -19,6 +20,7 @@ tasks:
       meson build_speex -Dresampler=speex
       meson build_libsamplerate -Dresampler=libsamplerate
       meson build_fftw -Dfft=fftw
+#      meson build_sleef -Dfft=sleef
       meson build_kissfft -Dfft=kissfft
   - build: |
       cd rubberband
@@ -33,6 +35,8 @@ tasks:
       build_libsamplerate/rubberband -V
       ninja -C build_fftw
       meson test -C build_fftw
+#      ninja -C build_sleef
+#      meson test -C build_sleef
       build_fftw/rubberband -V
       ninja -C build_kissfft
       meson test -C build_kissfft

COMPILING.md

@@ -256,6 +256,13 @@ FFTW3       -Dfft=fftw      -DHAVE_FFTW3   GPL.
                                            A bit faster than built-in,
                                            a bit slower than Accelerate.
 
+SLEEF       -Dfft=sleef     -DHAVE_SLEEF   Usually very fast. Not as widely
+                                           distributed as FFTW3. Requires
+                                           both libsleef and libsleefdft.
+                                           Can be distributed with either
+                                           the Rubber Band GPL or
+                                           commercial licence.
+
 KissFFT     -Dfft=kissfft   -DHAVE_KISSFFT
                                            Single precision.
                                            Only indicated for use with

README.md

@@ -58,6 +58,7 @@ details.
 
  * FFTW3 - GPL; proprietary licence needed for redistribution
  * Intel IPP - Proprietary; licence needed for redistribution
+ * SLEEF - BSD-like
  * KissFFT - BSD-like
  * libsamplerate - BSD-like from version 0.1.9 onwards
  * Speex - BSD-like