The LLVMTableGen component is a special case that is excluded from libLLVM and
normally is only built as static library and linked into llvm-tblgen.

We need to have it as a shared library to be available for other projects such
as ldc.

This patch makes it even more special and forces it to be build and installed
as separate shared library.

Index: llvm-8.0.0rc3.src/cmake/modules/AddLLVM.cmake
===================================================================
--- llvm-8.0.0rc3.src.orig/cmake/modules/AddLLVM.cmake
+++ llvm-8.0.0rc3.src/cmake/modules/AddLLVM.cmake
@@ -541,7 +541,7 @@ function(llvm_add_library name)
   if(ARG_MODULE AND LLVM_EXPORT_SYMBOLS_FOR_PLUGINS AND ARG_PLUGIN_TOOL AND (WIN32 OR CYGWIN))
     # On DLL platforms symbols are imported from the tool by linking against it.
     set(llvm_libs ${ARG_PLUGIN_TOOL})
-  elseif (NOT ARG_COMPONENT_LIB)
+  elseif (NOT ARG_COMPONENT_LIB OR (${name} STREQUAL "LLVMTableGen" AND LLVM_BUILD_LLVM_DYLIB))
     if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
       set(llvm_libs LLVM)
     else()
Index: llvm-8.0.0rc3.src/cmake/modules/TableGen.cmake
===================================================================
--- llvm-8.0.0rc3.src.orig/cmake/modules/TableGen.cmake
+++ llvm-8.0.0rc3.src/cmake/modules/TableGen.cmake
@@ -115,7 +115,8 @@ macro(add_tablegen target project)
     set(LLVM_ENABLE_OBJLIB ON)
   endif()
 
-  add_llvm_executable(${target} DISABLE_LLVM_LINK_LLVM_DYLIB ${ARGN})
+  add_llvm_executable(${target} ${ARGN})
+  target_link_libraries(${target} PRIVATE LLVMTableGen)
   set(LLVM_LINK_COMPONENTS ${${target}_OLD_LLVM_LINK_COMPONENTS})
 
   set(${project}_TABLEGEN "${target}" CACHE
Index: llvm-8.0.0rc3.src/lib/TableGen/CMakeLists.txt
===================================================================
--- llvm-8.0.0rc3.src.orig/lib/TableGen/CMakeLists.txt
+++ llvm-8.0.0rc3.src/lib/TableGen/CMakeLists.txt
@@ -1,3 +1,7 @@
+if (LLVM_BUILD_LLVM_DYLIB)
+    set(MAYBE_SHARED SHARED)
+endif()
+
 add_llvm_component_library(LLVMTableGen
   DetailedRecordsBackend.cpp
   Error.cpp
@@ -9,6 +13,8 @@ add_llvm_library(LLVMTableGen
   TGLexer.cpp
   TGParser.cpp
 
+  ${MAYBE_SHARED}
+
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/TableGen