Tonight I updated my archlinux installation. It updated vapoursynth from R48 to R49.
If I compile and run a file I get the message: $ ./modifyframe /home/jose/src/VapourSynth.nim/src/libs/libvapoursynth.so: undefined symbol: pthread_create could not load: /home/jose/src/VapourSynth.nim/src/libs/libvapoursynth.so But if I run one of the files compiled before the update it works fine. Any clue about what might be happening?