Also install c10d headers with .h extension (pytorch#73422)

Summary:
Pull Request resolved: pytorch#73422

Fixes pytorch#73421
ghstack-source-id: 149978120

Test Plan: None

Reviewed By: cbalioglu

Differential Revision: D34475711

fbshipit-source-id: 9e4d1d57021cbff51f53762b32bbfffbf3f81c4c
(cherry picked from commit 72ff35e)

caffe2/CMakeLists.txt

@@ -1094,7 +1094,7 @@ endif()
     FILES_MATCHING PATTERN "*.h")
   install(DIRECTORY "${TORCH_SRC_DIR}/csrc/distributed/c10d"
     DESTINATION ${TORCH_INSTALL_INCLUDE_DIR}
-    FILES_MATCHING PATTERN "*.hpp")
+    FILES_MATCHING PATTERN "*.h" PATTERN "*.hpp")
   install(FILES
     "${TORCH_SRC_DIR}/script.h"
     "${TORCH_SRC_DIR}/extension.h"

setup.py

@@ -981,6 +981,7 @@ def print_box(msg):
                 'include/c10/cuda/impl/*.h',
                 'include/c10/hip/*.h',
                 'include/c10/hip/impl/*.h',
+                'include/c10d/*.h',
                 'include/c10d/*.hpp',
                 'include/caffe2/**/*.h',
                 'include/torch/*.h',