TableGen: include in libLLVM-*.so

[nhaehnle]

Summary

Use of TableGen has grown over the years, so the claim that it is for
internal use only carries less and less water.

The main motivation for adding it to the dylib is to cleanup linking of
tablegen tools outside of llvm itself.

See: https://discourse.llvm.org/t/rfc-cleaning-up-how-we-link-tablegen-tools/66678

llvm/tools/llvm-shlib/CMakeLists.txt

 
 if(LLVM_BUILD_LLVM_DYLIB)
   if(MSVC)
     message(FATAL_ERROR "Generating libLLVM is not supported on MSVC")
   endif()
 
   llvm_map_components_to_libnames(LIB_NAMES ${LLVM_DYLIB_COMPONENTS})
 
-  # Exclude libLLVMTableGen for the following reasons:
-  #  - it is only used by internal *-tblgen utilities;
-  list(REMOVE_ITEM LIB_NAMES "LLVMTableGen")
-
   if(LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
     set(LLVM_EXPORTED_SYMBOL_FILE ${LLVM_DYLIB_EXPORTED_SYMBOL_FILE})
     add_custom_target(libLLVMExports DEPENDS ${LLVM_EXPORTED_SYMBOL_FILE})
   endif()
 
   if (LLVM_LINK_LLVM_DYLIB)
     set(INSTALL_WITH_TOOLCHAIN INSTALL_WITH_TOOLCHAIN)
   endif()