[Submodule] Remove zstd dependency (pytorch#126485)

After searching in the codebase, it seems that zstd is not in use now.

Pull Request resolved: pytorch#126485
Approved by: https://github.com/ezyang

.gitmodules

@@ -50,10 +50,6 @@
     ignore = dirty
     path = third_party/psimd
     url = https://github.com/Maratyszcza/psimd.git
-[submodule "third_party/zstd"]
-    ignore = dirty
-    path = third_party/zstd
-    url = https://github.com/facebook/zstd.git
 [submodule "third_party/cpuinfo"]
     ignore = dirty
     path = third_party/cpuinfo

CMakeLists.txt

@@ -283,7 +283,6 @@ option(USE_VULKAN_FP16_INFERENCE "Vulkan - Use fp16 inference" OFF)
 option(USE_VULKAN_RELAXED_PRECISION "Vulkan - Use relaxed precision math in the kernels (mediump)" OFF)
 # option USE_XNNPACK: try to enable xnnpack by default.
 option(USE_XNNPACK "Use XNNPACK" ON)
-option(USE_ZSTD "Use ZSTD" OFF)
 option(USE_ROCM_KERNEL_ASSERT "Use Kernel Assert for ROCm" OFF)
 # Ensure that an ITT build is the default for x86 CPUs
 cmake_dependent_option(
@@ -413,7 +412,6 @@ option(USE_SYSTEM_FXDIV "Use system-provided fxdiv." OFF)
 option(USE_SYSTEM_BENCHMARK "Use system-provided google benchmark." OFF)
 option(USE_SYSTEM_ONNX "Use system-provided onnx." OFF)
 option(USE_SYSTEM_XNNPACK "Use system-provided xnnpack." OFF)
-option(USE_SYSTEM_ZSTD "Use system-provided zstd." OFF)
 option(USE_GOLD_LINKER "Use ld.gold to link" OFF)
 if(USE_SYSTEM_LIBS)
   set(USE_SYSTEM_CPUINFO ON)
@@ -435,9 +433,6 @@ if(USE_SYSTEM_LIBS)
   if(USE_TBB)
     set(USE_SYSTEM_TBB ON)
   endif()
-  if(USE_ZSTD)
-    set(USE_SYSTEM_ZSTD ON)
-  endif()
 endif()
 
 # Used when building Caffe2 through setup.py

cmake/Dependencies.cmake

@@ -1426,25 +1426,6 @@ if(USE_NNAPI AND NOT ANDROID)
   caffe2_update_option(USE_NNAPI OFF)
 endif()
 
-if(USE_ZSTD)
-  if(USE_SYSTEM_ZSTD)
-    find_package(zstd REQUIRED)
-    if(TARGET zstd::libzstd_shared)
-      set(ZSTD_TARGET zstd::libzstd_shared)
-    else()
-      set(ZSTD_TARGET zstd::libzstd_static)
-    endif()
-    list(APPEND Caffe2_DEPENDENCY_LIBS ${ZSTD_TARGET})
-    get_property(ZSTD_INCLUDE_DIR TARGET ${ZSTD_TARGET} PROPERTY INTERFACE_INCLUDE_DIRECTORIES)
-    include_directories(SYSTEM ${ZSTD_INCLUDE_DIR})
-  else()
-    list(APPEND Caffe2_DEPENDENCY_LIBS libzstd_static)
-    include_directories(SYSTEM ${CMAKE_CURRENT_LIST_DIR}/../third_party/zstd/lib)
-    add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/../third_party/zstd/build/cmake)
-    set_property(TARGET libzstd_static PROPERTY POSITION_INDEPENDENT_CODE ON)
-  endif()
-endif()
-
 # ---[ Onnx
 if(CAFFE2_CMAKE_BUILDING_WITH_MAIN_REPO AND NOT INTERN_DISABLE_ONNX)
   if(EXISTS "${CAFFE2_CUSTOM_PROTOC_EXECUTABLE}")

setup.py

@@ -151,9 +151,6 @@
 #   USE_REDIS
 #     Whether to use Redis for distributed workflows (Linux only)
 #
-#   USE_ZSTD
-#     Enables use of ZSTD, if the libraries are found
-#
 #   USE_ROCM_KERNEL_ASSERT=1
 #     Enable kernel assert in ROCm platform
 #