builder: error on implicit function declaration

[kbkpbot]

Turn implicit function declaration from warning to error.
This help fix issue such as #14783

[spytheman]

Imho that is not necessary.
V already supports -cstrict , which turns many other warnings into errors, including that specific one:

[kbkpbot]

Because -cstrict is not on by default, so I think it is better add -Werror=implicit-function-declaration to compile options.
You can see in some CI fail, for example, the Build Vinix / vinix-build (pull_request), it has implicit declaration of function ‘mount’ .

[kbkpbot]

CI fail https://github.com/vlang/v/actions/runs/20957079817/job/60224272531?pr=26343 is because vsql use flock which should include in #include <sys/file.h>, but https://github.com/elliotchance/vsql/blob/main/vsql/flock_nix.c.v use #include <fcntl.h>

https://github.com/elliotchance/vsql/blob/87910673dfdbdec246a9801983bbcea7db363472/vsql/flock_nix.c.v#L9C1-L11

I am not sure this repo is maintained or not....

[JalonSolov]

Yes, vsql is maintained. Elliot is on the V discord... just posted something recently.

Make an issue for him on the vsql repo.

[kbkpbot]

Yes, vsql is maintained. Elliot is on the V discord... just posted something recently.

Make an issue for him on the vsql repo.

Thank you. I post some issues at upstream, hope they can be fixed.