Revert "Move at::{Refcounted,}MapAllocator to c10 (pytorch#109881)"

This reverts commit 68a1219.

Reverted pytorch#109881 on behalf of https://github.com/kit1980 due to breaking internal builds, undefined symbol: _ZN3c1022RefcountedMapAllocator6decrefEv ([comment](pytorch#109881 (comment)))

BUILD.bazel

@@ -1643,8 +1643,7 @@ cc_library(
     name = "shm",
     srcs = glob(["torch/lib/libshm/*.cpp"]),
     deps = [
-        ":torch_headers",
-        "//c10",
+        ":torch",
     ],
 )
 

aten/src/ATen/CMakeLists.txt

@@ -337,6 +337,28 @@ if(UNIX AND NOT APPLE)
    endif(NEED_LIBRT)
 endif(UNIX AND NOT APPLE)
 
+if(UNIX)
+  set(CMAKE_EXTRA_INCLUDE_FILES "sys/mman.h")
+  CHECK_FUNCTION_EXISTS(mmap HAVE_MMAP)
+  if(HAVE_MMAP)
+    add_definitions(-DHAVE_MMAP=1)
+  endif(HAVE_MMAP)
+  # done for lseek: https://www.gnu.org/software/libc/manual/html_node/File-Position-Primitive.html
+  add_definitions(-D_FILE_OFFSET_BITS=64)
+  CHECK_FUNCTION_EXISTS(shm_open HAVE_SHM_OPEN)
+  if(HAVE_SHM_OPEN)
+    add_definitions(-DHAVE_SHM_OPEN=1)
+  endif(HAVE_SHM_OPEN)
+  CHECK_FUNCTION_EXISTS(shm_unlink HAVE_SHM_UNLINK)
+  if(HAVE_SHM_UNLINK)
+    add_definitions(-DHAVE_SHM_UNLINK=1)
+  endif(HAVE_SHM_UNLINK)
+  CHECK_FUNCTION_EXISTS(malloc_usable_size HAVE_MALLOC_USABLE_SIZE)
+  if(HAVE_MALLOC_USABLE_SIZE)
+    add_definitions(-DHAVE_MALLOC_USABLE_SIZE=1)
+  endif(HAVE_MALLOC_USABLE_SIZE)
+endif(UNIX)
+
 ADD_DEFINITIONS(-DUSE_EXTERNAL_MZCRC)
 
 if(NOT MSVC)