gnu: tensorflow-lite: Fix build.

* gnu/packages/machine-learning.scm (tensorflow-lite): Fix build.
[inputs]: Change flatbuffers-next to flatbuffers-23.1.

* gnu/packages/serialization.scm (flatbuffers-23.1): New variable.

Change-Id: I257c3563cb91cbf8e0f0874367aafced248ab4dc
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/machine-learning.scm

@@ -3487,7 +3487,7 @@ advanced research.")
        ("cpuinfo" ,cpuinfo)
        ("eigen" ,eigen)
        ("fp16" ,fp16)
-       ("flatbuffers" ,flatbuffers-next)
+       ("flatbuffers" ,flatbuffers-23.1)
        ("gemmlowp" ,gemmlowp)
        ("mesa-headers" ,mesa-headers)
        ("neon2sse" ,neon2sse)

gnu/packages/serialization.scm

@@ -899,6 +899,25 @@ C#, C, Go, Java, JavaScript, PHP, and Python.  It was originally created for
 game development and other performance-critical applications.")
     (license license:asl2.0)))
 
+(define-public flatbuffers-23.1
+    ;; needed explicitly by tensorflow-lite 2.13.1
+  (package
+    (inherit flatbuffers)
+    (version "23.1.21")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/google/flatbuffers")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name "flatbuffers" version))
+              (sha256
+               (base32
+                "1z3a6l8g2y53i5xzraswfs2i0i3kk52zv7nzc2q3fgisbyiri3pz"))))
+    (arguments
+     (substitute-keyword-arguments (package-arguments flatbuffers)
+       ((#:configure-flags flags #~'())
+        #~(append #$flags '("-DCMAKE_POSITION_INDEPENDENT_CODE=ON")))))))
+
 (define-public flatbuffers-next
   (package
     (inherit flatbuffers)