Describe the bug

CONFIG_PICOLIBC is currently incompatible with sparse due to some .h files complexities.

EDIT October 2nd with newer, simpler, SOF-free reproduction

# Compiles and provides all sparse warnings
west build -b intel_adsp_cavs25  samples/hello_world -p -- \
 -DCONFIG_MINIMAL_LIBC=y -DZEPHYR_SCA_VARIANT=sparse

# Does not compile and can't provide some sparse warnings
west build -b intel_adsp_cavs25  samples/hello_world -p -- \
 -DCONFIG_PICOLIBC=y -DZEPHYR_SCA_VARIANT=sparse 

Slower, -j1 version that does not bury the relevant error:

west build -b intel_adsp_cavs25  samples/hello_world -p -- \
 -DCONFIG_PICOLIBC=y  -DZEPHYR_SCA_VARIANT=sparse

ninja -j1 -C build

Building C object zephyr/lib/libc/picolibc/CMakeFiles/lib__libc__picolibc.dir/libc-hooks.c.obj
zephyr/lib/libc/picolibc/libc-hooks.c: note: in included file:
zephyr/include/zephyr/posix/sys/stat.h:40:11: error: unable to open 'sys/_timespec.h'

OLDER, initial and more complex reproduction that requires SOF. Kept here for completeness, you can probably skip it.

Commit f0daf90 switched CONFIG_PICOLIBC on by default. This broke the "sparse" analyzer used in the SOF project:

https://github.com/thesofproject/sof/actions/runs/6247162197/job/16959223474?pr=8235

/zep_workspace/zephyr/lib/os/printk.c:123:33: error: undefined identifier 'FDEV_SETUP_STREAM'
/zep_workspace/zephyr/lib/os/printk.c:144:32: error: undefined identifier 'FDEV_SETUP_STREAM'
/zep_workspace/zephyr/lib/os/printk.c:144:49: error: invalid initializer
/zep_workspace/zephyr/include/zephyr/posix/sys/stat.h:40:11: error: unable to open 'sys/_timespec.h'

Note this is not just a sparse warning or false positive: compilation with sparse actually FAILS, it cannot even complete.

To Reproduce

Detailed steps at

• west.yml: update Zephyr to 492517b918d26 thesofproject/sof#8235 (comment)

Expected behavior

Sparse can still sparse.

Impact

Broken SOF CI

Logs and console output

• west.yml: update Zephyr to 492517b918d26 thesofproject/sof#8235 (comment)

Environment (please complete the following information):

Github runner Ubuntu 22.04 LTS

Zephyr CI image with Zephyr SDK + marc-hb/sparse@3848a76ba49f336

zephyr commit 3415905 and SOF commit 75337b41eb51)

Additional context

These two workarounds were tested successfully:

• git revert f0daf90

• CONFIG_MINIMAL_LIBC=y as in ~/SOF/sof/scripts/xtensa-build-zephyr.py -p mtl --cmake-args=-DZEPHYR_SCA_VARIANT=sparse --cmake-args=-DCONFIG_LOG_USE_VLA=n --cmake-args=-DCONFIG_MINIMAL_LIBC=y