Do not import `sys/sendfile.h`
Do not import `sys/sendfile.h`

It now causes an error because emsdk removed it.

Signed-off-by: Yuki Okushi <0a792b09e3c7d426e6dc7b64bc4e95f557d97c14@2k36.org>

rust-lang/libc,rust-lang/libc,rust-lang/libc