Threads not found when pulled in as a meson subproject

[satmandu]

Weston is pulling in neatvnc as a meson subproject, but the current neatvnc version is having difficulty with figuring out threads support when pulled in as a meson subproject.

I get this error:

 [172/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_enc_interface.c.o
[173/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_pixels.c.o
[174/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_logging.c.o
FAILED: [code=1] subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_logging.c.o 
cc -Isubprojects/neatvnc/libneatvnc.so.0.0.0.p -Isubprojects/neatvnc -I../subprojects/neatvnc -I../subprojects/neatvnc/include -I../subprojects/aml/include -I/usr/local/include/pixman-1 -I/usr/local/include/libdrm -I/usr/local/include/p11-kit-1 -flto=auto -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -std=gnu11 -O3 '-DPROJECT_VERSION="v0.9.5-36ef59a (HEAD)"' -D_GNU_SOURCE -fvisibility=hidden -DAML_UNSTABLE_API=1 -Wmissing-prototypes -Wno-unused-parameter -Wno-format-truncation -DNDEBUG -O3 -pipe -ffat-lto-objects -fPIC -fuse-ld=mold -flto=auto -fPIC -MD -MQ subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_logging.c.o -MF subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_logging.c.o.d -o subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_logging.c.o -c ../subprojects/neatvnc/src/logging.c
../subprojects/neatvnc/src/logging.c:28:10: fatal error: threads.h: No such file or directory
   28 | #include <threads.h>
      |          ^~~~~~~~~~~
compilation terminated.
[175/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_server.c.o
[176/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_cursor.c.o
[177/594] Compiling C object subprojects/neatvnc/libneatvnc.so.0.0.0.p/src_damage-refinery.c.o
ninja: build stopped: subcommand failed.

The downstream discussion is here: https://gitlab.freedesktop.org/wayland/weston/-/issues/1049#note_3058377

Happy to help test any changes to help get the weston project working with neatvnc...

[any1]

This header should be available if you have a compiler that supports C11. Did you try adding the threads dependency as mvlad suggested?

[satmandu]

How would you recommend we do that? We're using GCC 15.2 to build.

I suspect something is happening such that the build fails as a meson subproject, but the issue might be simpler.

[any1]

How would you recommend we do that?

Add the threads dependency to the meson.build file the same way it's done in aml, like mvlad suggested