Hello, I'm running Devuan (Debian) Linux. I'm splitting this mail thread from the "Cannot use QSV on Intel 265K ffmpeg 8.0" as this seems to be a different topic. On Tue, 20 Jan 2026 14:07:21 +0000 Peter van den Houten via ffmpeg-user <ffmpeg-user@ffmpeg.org> wrote:

3) I played around with stdbit.h and I'm puzzled as to why your build is ignoring FFmpeg's compat/stdbit/stdbit.h

To test, I moved mine away, causing the build to fail, then added a "--extra-cflags=-I/new_location" and it worked as it should.

So I tried adding the --extra-cflags="-Icompat/" both with and without stdbit/ dir as well as specifying it as an absolute path to no effect. I also tried listing the file itself, again, without effect. Checking the log, the option is being passed to gcc -- which makes this even more weird. % gcc --version gcc (Debian 12.2.0-14+deb12u1) 12.2.0 I then installed stdbit.h into /usr/include/ but I'm still getting the same error. The last lines of config.log read: BEGIN /tmp/ffconf.BwXd0JCb/test.c 1 #include <stdbit.h> 2 #include <assert.h> 3 int main(void) { static_assert(__STDC_VERSION_STDBIT_H__ >= 202311L, "Compiler lacks stdbit.h"); return 0; } END /tmp/ffconf.BwXd0JCb/test.c gcc -D_ISOC11_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -DPIC -O2 -mtune=native -march=native -I=/root/working/ffmpeg-8.0/compat/stdbit/ -march=native -std=c17 -fomit-frame-pointer -fPIC -pthread -I/usr/local/include/oapv -I/usr/include/lilv-0 -I/usr/include/serd-0 -I/usr/include/sord-0 -I/usr/include/sratom-0 -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/fribidi -I/usr/include/libxml2 -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/bs2b -I/usr/local/include -I/usr/include/libdrm -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -DHWY_SHARED_DEFINE -I/usr/local/include -I/usr/lib/x86_64-linux-gnu/pkgconfig/../../../include -I/usr/lib/x86_64-linux-gnu/pkgconfig/../../../include/vpl -DMFX_DEPRECATED_OFF -I/usr/include/openjpeg-2.5 -I/usr/include/x86_64-linux-gnu -I/usr/include/opus -I/usr/include/opus -I/usr/include/rav1e -I/usr/include/librsvg-2.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/x86_64-linux-gnu -I/usr/include/webp -pthread -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/p11-kit-1 -I/usr/include/srt -I/usr/include/svt-av1 -DEB_DLL -I/usr/include/leptonica -I/usr/local/include -I/usr/local/include -I/usr/include/webp -I/usr/include/webp -DX264_API_IMPORTS -I/usr/local/include -I/usr/local/include/xevd -I/usr/local/include/xeve -isystem /usr/include/mit-krb5 -I/usr/include/pgm-5.3 -I/usr/include/libxml2 -I/usr/include/libxml2 -I/usr/include/AL -I/usr/include/sphinxbase -I/usr/include/pocketsphinx -I/usr/include/x86_64-linux-gnu -I/usr/include/x86_64-linux-gnu/sphinxbase -I/usr/include/libdrm -g -Wall -Wdisabled-optimization -Wpointer-arith -Wredundant-decls -Wwrite-strings -Wtype-limits -Wundef -Wmissing-prototypes -Wstrict-prototypes -Wempty-body -Wno-parentheses -Wno-switch -Wno-format-zero-length -Wno-pointer-sign -Wno-unused-const-variable -Wno-bool-operation -Wno-char-subscripts -O3 -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -Werror=format-security -Werror=implicit-function-declaration -Werror=missing-prototypes -Werror=return-type -Werror=vla -Wformat -fdiagnostics-color=auto -Wno-maybe-uninitialized -c -o /tmp/ffconf.BwXd0JCb/test.o /tmp/ffconf.BwXd0JCb/test.c gcc -march=native -Wl,--as-needed -Wl,-z,noexecstack -Wl,-rpath-link=:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil -o /tmp/ffconf.BwXd0JCb/test /tmp/ffconf.BwXd0JCb/test.o ERROR: vaapi requested but not found I ran the above commands but with the file as tmp.c, tmp.o, tmp in the ffmpeg dir and it worked just fine. I'm really at a loss on how to proceed with this one. Like gcc should print an error message which aught to be recorded. I can't find any debug or verbose option for the configure script. Log attached. Any Ideas? Thanks, David