libavutil/adler32.o: file not recognized

[Mikhail T.]

Trying to build ffmpeg today, getting the below error:

    cc -shared -Wl,-soname,libavutil.so.56 -Wl,-Bsymbolic -Llibavcodec
    -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample
    -Llibavutil -Llibpostproc -Llibswscale -Llibswresample
    -fstack-protector-strong -L/opt/lib -Wl,--as-needed
    -Wl,-z,noexecstack -Wl,--warn-common
    -Wl,-rpath-link=:libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil:libavresample
    -O3 -fno-math-errno -fno-signed-zeros  -o libavutil/libavutil.so.56
    *libavutil/adler32.o* libavutil/aes.o libavutil/aes_ctr.o
    libavutil/audio_fifo.o libavutil/avsscanf.o libavutil/avstring.o
    libavutil/base64.o libavutil/blowfish.o libavutil/bprint.o
    libavutil/buffer.o libavutil/camellia.o libavutil/cast5.o
    libavutil/channel_layout.o libavutil/color_utils.o libavutil/cpu.o
    libavutil/crc.o libavutil/des.o libavutil/dict.o libavutil/display.o
    libavutil/dovi_meta.o libavutil/downmix_info.o
    libavutil/encryption_info.o libavutil/error.o libavutil/eval.o
    libavutil/fifo.o libavutil/file.o libavutil/file_open.o
    libavutil/fixed_dsp.o libavutil/float_dsp.o libavutil/frame.o
    libavutil/hash.o libavutil/hdr_dynamic_metadata.o libavutil/hmac.o
    libavutil/hwcontext.o libavutil/hwcontext_opencl.o
    libavutil/hwcontext_qsv.o libavutil/hwcontext_vdpau.o
    libavutil/imgutils.o libavutil/integer.o libavutil/intmath.o
    libavutil/lfg.o libavutil/lls.o libavutil/log.o libavutil/log2_tab.o
    libavutil/lzo.o libavutil/mastering_display_metadata.o
    libavutil/mathematics.o libavutil/md5.o libavutil/mem.o
    libavutil/murmur3.o libavutil/opt.o libavutil/parseutils.o
    libavutil/pixdesc.o libavutil/pixelutils.o libavutil/random_seed.o
    libavutil/rational.o libavutil/rc4.o libavutil/reverse.o
    libavutil/ripemd.o libavutil/samplefmt.o libavutil/sha.o
    libavutil/sha512.o libavutil/slicethread.o libavutil/spherical.o
    libavutil/stereo3d.o libavutil/tea.o libavutil/threadmessage.o
    libavutil/time.o libavutil/timecode.o libavutil/tree.o
    libavutil/twofish.o libavutil/tx.o libavutil/tx_double.o
    libavutil/tx_float.o libavutil/tx_int32.o libavutil/utils.o
    libavutil/video_enc_params.o libavutil/x86/cpu.o
    libavutil/x86/cpuid.o libavutil/x86/fixed_dsp.o
    libavutil/x86/fixed_dsp_init.o libavutil/x86/float_dsp.o
    libavutil/x86/float_dsp_init.o libavutil/x86/imgutils.o
    libavutil/x86/imgutils_init.o libavutil/x86/lls.o
    libavutil/x86/lls_init.o libavutil/x86/pixelutils.o
    libavutil/x86/pixelutils_init.o libavutil/xga_font_data.o
    libavutil/xtea.o  -pthread -lvdpau -lX11 -lm -L/opt/lib -lmfx
    -L/opt/lib -lOpenCL -lXv -lX11 -lXext
    libavutil/adler32.o: file not recognized: File format not recognized
    cc: error: linker command failed with exit code 1 (use -v to see
    invocation)

The adler32.o is simply the first on the line. All of the object files 
in libavutil are, according to file(1) "LLVM IR bitcode".

Please, advise. Thank you. Yours,

    -mi