[lldb] Move create_relative_symlink function up in CMake hierarchy

Configuring lldb with `LLDB_ENABLE_PYTHON=OFF` and `LLDB_ENABLE_LUA=ON` results in a CMake error:

    CMake Error at lldb/bindings/lua/CMakeLists.txt:47 (create_relative_symlink):
      Unknown CMake command "create_relative_symlink".
    Call Stack (most recent call first):
      lldb/CMakeLists.txt:117 (finish_swig_lua)

This is because the CMake function `create_relative_symlink` only exists in `lldb/bindings/python/CMakeLists.txt`, and not in `lldb/bindings/lua/CMakeLists.txt`.

Move the function to `lldb/bindings/CMakeLists.txt`, so it is available for all language bindings.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D114465

lldb/bindings/CMakeLists.txt

@@ -31,6 +31,20 @@ set(SWIG_COMMON_FLAGS
   ${DARWIN_EXTRAS}
 )
 
+function(create_relative_symlink swig_target dest_file output_dir output_name)
+  get_filename_component(dest_file ${dest_file} ABSOLUTE)
+  get_filename_component(output_dir ${output_dir} ABSOLUTE)
+  file(RELATIVE_PATH rel_dest_file ${output_dir} ${dest_file})
+  if(CMAKE_HOST_UNIX)
+    set(LLVM_LINK_OR_COPY create_symlink)
+  else()
+    set(LLVM_LINK_OR_COPY copy)
+  endif()
+  add_custom_command(TARGET ${swig_target} POST_BUILD VERBATIM
+    COMMAND ${CMAKE_COMMAND} -E ${LLVM_LINK_OR_COPY} ${rel_dest_file} ${output_name}
+    WORKING_DIRECTORY ${output_dir})
+endfunction()
+
 if (LLDB_ENABLE_PYTHON)
   add_subdirectory(python)
 endif()

lldb/bindings/python/CMakeLists.txt

@@ -52,20 +52,6 @@ function(create_python_package swig_target working_dir pkg_dir)
     WORKING_DIRECTORY ${working_dir})
 endfunction()
 
-function(create_relative_symlink swig_target dest_file output_dir output_name)
-  get_filename_component(dest_file ${dest_file} ABSOLUTE)
-  get_filename_component(output_dir ${output_dir} ABSOLUTE)
-  file(RELATIVE_PATH rel_dest_file ${output_dir} ${dest_file})
-  if(CMAKE_HOST_UNIX)
-    set(LLVM_LINK_OR_COPY create_symlink)
-  else()
-    set(LLVM_LINK_OR_COPY copy)
-  endif()
-  add_custom_command(TARGET ${swig_target} POST_BUILD VERBATIM
-    COMMAND ${CMAKE_COMMAND} -E ${LLVM_LINK_OR_COPY} ${rel_dest_file} ${output_name}
-    WORKING_DIRECTORY ${output_dir})
-endfunction()
-
 function(finish_swig_python swig_target lldb_python_bindings_dir lldb_python_target_dir)
   # Add a Post-Build Event to copy over Python files and create the symlink to
   # liblldb.so for the Python API(hardlink on Windows).