librmt/rmtopen: Prefer <signal.h> over <sys/signal.h>

[sandeen: fixes build with musl libc]

Signed-off-by: Felix Janda <felix.janda@posteo.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

1 file changed