config/git: import suckless sbase

i currently use the output of sha512sum in several
places of xbmk, which is a bit unreliable in case
output changes.

other cases where i use util outputs in variables
are probably reliable, because i'm using mostly
posix utilities in those.

to mitigate this, i now import suckless sbase, which
has a reasonable sha512sum implementation.

*every* binary it builds is being placed in build.list,
because i'll probably start using more of them.

for example, i may start modifying the "date"
implementation, adding the GNU-specific options that
i need as mentioned on init.sh

i'm importing it in util/ because the sha512sum
util is needed for verifying project sources, so
if sbase itself is a "project source", that means
we can into a chicken and egg bootstrapping problem.

this is sbase at revision:
055cc1ae1b3a13c3d8f25af0a4a3316590efcd48

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/sbase/chroot.1

@@ -0,0 +1,25 @@
+.Dd October 8, 2015
+.Dt CHROOT 1
+.Os sbase
+.Sh NAME
+.Nm chroot
+.Nd run a command or shell with a different root directory
+.Sh SYNOPSIS
+.Nm
+.Ar dir
+.Op Ar cmd Op Ar arg ...
+.Sh DESCRIPTION
+.Nm
+runs
+.Ar cmd
+after changing the root directory to
+.Ar dir
+with the
+.Xr chroot 2
+system call and after changing the working directory to the new root.
+If
+.Ar cmd
+is not specified, an interactive shell is started in the new root.
+.Sh SEE ALSO
+.Xr chdir 2 ,
+.Xr chroot 2