From 5c533a0232be2e2e899756b1019c8863a259e6ed Mon Sep 17 00:00:00 2001
From: Phillip Cloud <417981+cpcloud@users.noreply.github.com>
Date: Fri, 18 Jun 2021 05:46:37 -0400
Subject: [PATCH] tensorflow-lite: set CXXSTANDARD to c++17 (#127209)

---
 .../science/math/tensorflow-lite/default.nix      | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/science/math/tensorflow-lite/default.nix b/pkgs/development/libraries/science/math/tensorflow-lite/default.nix
index f407303d9878..cf2346bad271 100644
--- a/pkgs/development/libraries/science/math/tensorflow-lite/default.nix
+++ b/pkgs/development/libraries/science/math/tensorflow-lite/default.nix
@@ -83,6 +83,12 @@ stdenv.mkDerivation rec {
       url = "https://github.com/tensorflow/tensorflow/commit/f3c4f4733692150fd6174f2cd16438cfaba2e5ab.patch";
       sha256 = "0zx4hbz679kn79f30159rl1mq74dg45cvaawii0cyv48z472yy4k";
     })
+    # TODO: remove on the next version bump
+    (fetchpatch {
+      name = "cxxstandard-var.patch";
+      url = "https://github.com/tensorflow/tensorflow/commit/9b128ae4200e10b4752f903492d1e7d11957ed5c.patch";
+      sha256 = "1q0izdwdji5fbyqll6k4dmkzfykyvvz5cvc6hysdj285nkn2wy6h";
+    })
   ];
 
   buildInputs = [ zlib flatbuffers ];
@@ -140,7 +146,14 @@ stdenv.mkDerivation rec {
       # tensorflow lite expects to compile abseil into `libtensorflow-lite.a`
       ln -s ${abseil-cpp.src} "$prefix/absl"
 
-      buildFlagsArray+=(INCLUDES="-I $PWD ${includes}" TARGET_TOOLCHAIN_PREFIX="" -j$NIX_BUILD_CORES all)
+      # set CXXSTANDARD=c++17 here because abseil-cpp in nixpkgs is set as
+      # such and would be used in dependents like libedgetpu
+      buildFlagsArray+=(
+        INCLUDES="-I $PWD ${includes}"
+        CXXSTANDARD="-std=c++17"
+        TARGET_TOOLCHAIN_PREFIX=""
+        -j$NIX_BUILD_CORES
+        all)
     '';
 
   installPhase = ''