gnu: Add libfdk 'FDK AAC' library.

* gnu/packages/audio.scm (libfdk): New variable.

gnu/packages/audio.scm

@@ -3549,3 +3549,37 @@ using ALSA, MPD, PulseAudio, or a FIFO buffer as its input.")
       (synopsis "Pro-quality GM soundfont")
       (description "Fluid-3 is Frank Wen's pro-quality GM soundfont.")
       (license license:expat))))
+
+(define-public libfdk
+  (let ((commit "2326faaf8f2cdf2c3a9108ccdaf1d7551aec543e")
+        (revision "0"))
+    (package
+      (name "libfdk")
+      ;; The latest upstream revision, with many bug fixes.
+      (version (git-version "0.1.6" revision commit))
+      (source
+        (origin
+          (method git-fetch)
+          (uri (git-reference
+                 (url "https://github.com/mstorsjo/fdk-aac")
+                 (commit commit)))
+          (file-name (git-file-name name version))
+          (sha256
+           (base32
+            "0yy6ndd9d61bwl283vl1r5kva2a4acc0f4r9g0sza156f2abr9ws"))))
+      (build-system gnu-build-system)
+      (native-inputs
+       `(("autoconf" ,autoconf)
+         ("automake" ,automake)
+         ("libtool" ,libtool)))
+      (home-page "https://github.com/mstorsjo/fdk-aac")
+      (synopsis "Fraunhofer FDK AAC library")
+      (description "FDK is a library for encoding and decoding Advanced Audio
+Coding (AAC) format audio, developed by Fraunhofer IIS, and included as part of
+Android.  It supports several Audio Object Types including MPEG-2 and MPEG-4 AAC
+LC, HE-AAC (AAC LC + SBR), HE-AACv2 (LC + SBR + PS) as well AAC-LD (low delay)
+and AAC-ELD (enhanced low delay) for real-time communication.  The encoding
+library supports sample rates up to 96 kHz and up to eight channels (7.1
+surround).")
+      (license (license:fsf-free "https://github.com/mstorsjo/fdk-aac/blob/master/NOTICE"
+                                 "https://www.gnu.org/licenses/license-list.html#fdk")))))