libLTO.{so,dylib}: remove unused non-LTO symbols

These dissembler symbols are not used by LTO (see Apple ld64's use
in check-llvm-tools-lto). On ELF platforms, these symbols are not defined and are
rejected by ld --no-undefined-version.

I think this is a more proper solution than D139932 and this fixes
-DBUILD_SHARED_LIBS=on for ELF as well.

llvm/tools/lto/CMakeLists.txt

@@ -19,11 +19,7 @@ set(SOURCES
   lto.cpp
   )
 
-if (LLVM_LINK_LLVM_DYLIB)
-  set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/lto.dylib.exports)
-else()
-  set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/lto.exports)
-endif()
+set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/lto.exports)
 
 if(CMAKE_SYSTEM_NAME STREQUAL AIX)
     set(LTO_LIBRARY_TYPE MODULE)

llvm/tools/lto/lto.exports

@@ -45,12 +45,6 @@ lto_codegen_compile_optimized
 lto_codegen_set_should_internalize
 lto_codegen_set_should_embed_uselists
 lto_set_debug_options
-LLVMCreateDisasm
-LLVMCreateDisasmCPU
-LLVMDisasmDispose
-LLVMDisasmInstruction
-LLVMSetDisasmOptions
-LLVMCreateDisasmCPUFeatures
 thinlto_create_codegen
 thinlto_codegen_dispose
 thinlto_codegen_add_module