Revert "Revert "Merge branch 'CA-135969' into xs64bit""

This reverts commit 0ef84c6b7c3a6f43e9e7315bbae5aec029f04e0d.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
CA-135969: block all other signals

And use sigaction for handling signals.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Merge branch 'CA-135969' into xs64bit

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #95 on xapi-project/blktap