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System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): NVIDIA Xavier Jetson AGX, JetPack 4.5.1 (Ubuntu 18.04.5)
• Mobile device (e.g. iPhone 8, Pixel 2, Samsung Galaxy) if the issue happens on mobile device: N/A
• TensorFlow installed from (source or binary): TFLite installed from source
• TensorFlow version: v2.5.0
• Python version: v3.6.9
• CMake version: v1.19.5
• Installed using virtualenv? pip? conda?: no
• Bazel version (if compiling from source): N/A
• GCC/Compiler version (if compiling from source): 7.5.0
• CUDA/cuDNN version: N/A
• GPU model and memory: N/A

Describe the problem

Installing TensorFlow Lite via Collective Knowledge (which uses CMake), as described in this Jupyter notebook, with a new patch to support v2.5.0, would go fine but then fail with a linking error with rdft2d.

Provide the exact sequence of commands / steps that you executed before running into the problem

$ ck install package --tags=lib,tflite,via-cmake,with.ruy,v2.5.0
$ ck compile program:image-classification-tflite --dep_add_tags.library=tflite,v2.5.0
...
/home/katya/CK-TOOLS/lib-tflite-src-static-gcc-7.5.0-v2.5.0-with.ruy-linux-64/lib/libtensorflow-lite.a(rfft2d.cc.o): In function `tflite::ops::builtin::rfft2d::Rfft2dImpl(int, int, double**, int*, double*)':
rfft2d.cc:(.text+0x978): undefined reference to `rdft2d'
collect2: error: ld returned 1 exit status

Any other info / logs
What's weird is that despite the apparent intent to "export" fftsg2d which contains rdft2d, only fftsg.c.o would be linked against libtensorflow-lite.a. As a not completely logical workaround, I've managed just about to get it working with the following patch:

diff --git a/tensorflow/lite/tools/cmake/modules/fft2d/CMakeLists.txt b/tensorflow/lite/tools/cmake/modules/fft2d/CMakeLists.txt
index e7a5ed9b443..04c5b7c05db 100644
--- a/tensorflow/lite/tools/cmake/modules/fft2d/CMakeLists.txt
+++ b/tensorflow/lite/tools/cmake/modules/fft2d/CMakeLists.txt
@@ -37,7 +37,7 @@ target_include_directories(fft2d_alloc PUBLIC "${FFT2D_SOURCE_DIR}")
 add_library(fft2d_fft4f2d "${FFT2D_SOURCE_DIR}/fft4f2d.c")
 target_include_directories(fft2d_fft4f2d PRIVATE "${FFT2D_SOURCE_DIR}")

-add_library(fft2d_fftsg "${FFT2D_SOURCE_DIR}/fftsg.c")
+add_library(fft2d_fftsg "${FFT2D_SOURCE_DIR}/fftsg.c" "${FFT2D_SOURCE_DIR}/fftsg2d.c")

 # Requires implementation of fft2d_alloc.
 add_library(fft2d_fftsg2d "${FFT2D_SOURCE_DIR}/fftsg2d.c")