Allocate process 0's sigacts statically.
Set up the new process's sigacts before calling vm_fork().
Significantly restructure the way signal state for a process is stored.
Rather than using bitmasks to redundantly store the information kept
in the process's sigacts (because the sigacts was kept in the u-area),
hang sigacts directly off the process, and access it directly.

Simplify signal setup code tremendously by storing information in
the sigacts as an array of struct sigactions, rather than in a different
format, since userspace uses sigactions.

Make sigacts sharable by adding reference counting.
sigacts is no longer in in the u-area.
Significantly restructure the way signal state for a process is stored.
Rather than using bitmasks to redundantly store the information kept
in the process's sigacts (because the sigacts was kept in the u-area),
hang sigacts directly off the process, and access it directly.

Simplify signal setup code tremendously by storing information in
the sigacts as an array of struct sigactions, rather than in a different
format, since userspace uses sigactions.

Make sigacts sharable by adding reference counting.
Significantly restructure the way signal state for a process is stored.
Rather than using bitmasks to redundantly store the information kept
in the process's sigacts (because the sigacts was kept in the u-area),
hang sigacts directly off the process, and access it directly.

Simplify signal setup code tremendously by storing information in
the sigacts as an array of struct sigactions, rather than in a different
format, since userspace uses sigactions.

Make sigacts sharable by adding reference counting.