Error when compiling ffmpeg library supporting pthreads

Hello,When I use the EMCC compiler to execute the configure script of ffmpeg, I will encounter an error (**error: pthreads requested but not found**) when configuring the --enable pthreads option. When --disable pthreads is configured, I will compile normally.And I checked ffmpeg ./configure the configure instruction compiles --enable pthreads option normally.
**My execution instructions are as follows：**
`emconfigure ./configure --cc=emcc --prefix=../dist \
--target-os=none --arch=x86_32 --cpu=generic \
--enable-cross-compile --disable-debug --disable-stripping \
--disable-ffplay --disable-ffprobe --disable-asm \
--disable-doc --disable-devices --disable-avdevice --disable-postproc \
--enable-pthreads --disable-w32threads --disable-network \
--disable-hwaccels --disable-indevs --disable-outdevs \
--extra-cflags=-I/usr/include --extra-ldflags=-L/usr/lib \
--disable-sdl2 --disable-decoders --disable-encoders \
--disable-demuxers --disable-muxers --disable-filters \
--disable-bsfs --disable-protocols --enable-parsers \
--enable-protocol=file --enable-decoder=hevc \
--enable-decoder=h264 --enable-decoder=aac --enable-decoder=hevc \
--enable-decoder=adpcm_g722 --enable-decoder=g723_1 --enable-decoder=g729 \
--enable-decoder=mp2 --ranlib=emranlib; \`

**Details of errors I encountered**

`nm: /tmp/ffconf.PGpEUgP6/test.o: File format not recognized
ERROR: pthreads requested but not found

If you think configure made a mistake, make sure you are using the latest
version from Git. If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "ffbuild/config.log" produced by configure as this will help
solve the problem.
emconfigure: error: './configure --cc=emcc --prefix=../dist --target-os=none --arch=x86_32 --cpu=generic --enable-cross-compile --disable-debug --disable-stripping --disable-ffplay --disable-ffprobe --disable-asm --disable-doc --disable-devices --disable-avdevice --disable-postproc --enable-pthreads --disable-w32threads --disable-network --disable-hwaccels --disable-indevs --disable-outdevs --extra-cflags=-I/usr/include --extra-ldflags=-L/usr/lib --disable-sdl2 --disable-decoders --disable-encoders --disable-demuxers --disable-muxers --disable-filters --disable-bsfs --disable-protocols --enable-parsers --enable-protocol=file --enable-decoder=hevc --enable-decoder=h264 --enable-decoder=aac --enable-decoder=hevc --enable-decoder=adpcm_g722 --enable-decoder=g723_1 --enable-decoder=g729 --enable-decoder=mp2 --ranlib=emranlib' failed (returned 1)
`
What is the cause of this error or how should I check this error？
Thanks for all advice!