Hello @xta0,
With your podspec as exemple, I successfully added libtorch as a dependency of a private pod. Thank you for that !
Also I have a linker issue if I try to run a test target. I have the same issue, in the app using the private pod.
I tried with different version of libtorch, but I have the error with all of them (1.6.1, 1.7 and 1.7.1).
The error is :
Undefined symbols for architecture x86_64:
  "_clog_vlog_error", referenced from:
      pytorch_qnnp_log_error(char const*, ...) in libtorch_cpu.a(qconv_prepack.cpp.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Same error with arm64 if I try to run the tests on my device.
My podspec look like that :
  ...

  s.ios.deployment_target = '13.0'

  s.frameworks = [
  "Accelerate",
  "AssetsLibrary",
  "AVFoundation",
  "CoreGraphics",
  "CoreImage",
  "CoreMedia",
  "CoreVideo",
  "Foundation",
  "QuartzCore",
  "UIKit",
  "Vision"
  ]
  
  s.pod_target_xcconfig = { 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64' }
  s.user_target_xcconfig = { 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64' }
  
  s.source_files = 'PRIVATEPOD/Classes/**/*'
  s.resource_bundles = {
    'Json' => ['PRIVATEPOD/Resources/**/*{.json}'],
    'Model' => ['PRIVATEPOD/Resources/**/*{.pt}']
  }
  s.public_header_files = ["PRIVATEPOD/Classes/**/*{.h,.hpp}"]
  
  s.static_framework = true
  s.dependency 'OpenCV2', '4.2.0'
  s.dependency 'LibTorch'
  s.dependency 'ZIPFoundation', '~> 0.9'
  
  s.pod_target_xcconfig = {
      'HEADER_SEARCH_PATHS' => '$(inherited) "${PODS_ROOT}/LibTorch/install/include"'
  }
  s.library = 'c++', 'stdc++'
end

I tried many many things, but I’m stuck, and I cannot run my tests anymore :-/.
@xta0 do you have an idea to fix that ?
Thank you