'0 files from seeds' even if there exists some files in the input directory

[rottenworld]

I am using Angora to build llvm-libcxxabi in google fuzzer test suite, but I failed in fuzzing.
I put one seed file in the seeds folder but Angora thinks there was 0 file from seeds.
Thank you very much if you could help.

Build target:

ANGORA_DONT_OPTIMIZE=1 ANGORA_USE_ASAN=1 USE_FAST=1 $CXX $CXXFLAGS -std=c++11 ../main.cc ./fuzz/cxa_demangle_fuzzer.cpp ./src//cxa_demangle.cpp -I ./include -o llvm.fast
USE_TRACK=1 $CXX $CXXFLAGS -std=c++11 ../main.cc ./fuzz/cxa_demangle_fuzzer.cpp ./src//cxa_demangle.cpp -I ./include -o llvm.track

Fuzz:

~/Angora/angora_fuzzer -i seeds -o output -t ./track/llvm.track -- ./fast/llvm.fast @@

Error:

INFO  angora::depot::sync > sync       0 file from seeds.                                                                              
 ERROR angora::fuzz_main   > Failed to find any branches during dry run.                                                                
 ERROR angora::fuzz_main   > Please ensure that the binary has been instrumented and/or input directory is populated.                   
 ERROR angora::fuzz_main   > Please ensure that seed directory - "seeds" has any file.

I guess there might be something wrong in the build step. I would be thankful if you could tell me under which circumstances the error above will be raised.