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/printenv.1

@@ -0,0 +1,30 @@
+.Dd March 30, 2016
+.Dt PRINTENV 1
+.Os sbase
+.Sh NAME
+.Nm printenv
+.Nd print the environment or values of variables
+.Sh SYNOPSIS
+.Nm
+.Op Ar var ...
+.Sh DESCRIPTION
+.Nm
+prints the entire environment as key=value pairs if no
+.Ar var
+is given.
+Otherwise,
+.Nm
+prints only the value of each
+.Ar var
+one per line in the order specified.
+.Sh EXIT STATUS
+.Bl -tag -width Ds
+.It 0
+Successful completion.
+.It 1
+One or more queried variables were not found.
+.It > 1
+An error occurred.
+.El
+.Sh SEE ALSO
+.Xr env 1