Fix fuzzer objects building when LTO is enabled

Author: jiegec

compiler-rt/lib/fuzzer/CMakeLists.txt

@@ -147,7 +147,7 @@ if(OS_NAME MATCHES "Android|Linux|Fuchsia" AND
     set(cxx_${arch}_merge_dir "${CMAKE_CURRENT_BINARY_DIR}/cxx_${arch}_merge.dir")
     file(MAKE_DIRECTORY ${cxx_${arch}_merge_dir})
     add_custom_command(TARGET clang_rt.${name}-${arch} POST_BUILD
-      COMMAND ${CMAKE_CXX_COMPILER} ${target_cflags} -Wl,--whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" -Wl,--no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
+      COMMAND ${CMAKE_CXX_COMPILER} ${target_cflags} -flto -Wl,--whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" -Wl,--no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
       COMMAND ${CMAKE_OBJCOPY} --localize-hidden ${name}.o
       COMMAND ${CMAKE_COMMAND} -E remove "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>"
       COMMAND ${CMAKE_AR} qcs "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" ${name}.o