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/cmp.1

@@ -0,0 +1,49 @@
+.Dd October 8, 2015
+.Dt CMP 1
+.Os sbase
+.Sh NAME
+.Nm cmp
+.Nd compare two files
+.Sh SYNOPSIS
+.Nm
+.Op Fl l | Fl s
+.Ar file1 file2
+.Sh DESCRIPTION
+.Nm
+compares
+.Ar file1
+and
+.Ar file2
+byte by byte.
+If they differ,
+.Nm
+writes the first differing byte- and line-number to stdout.
+.Sh OPTIONS
+.Bl -tag -width Ds
+.It Fl l
+Print byte-number and bytes (in octal) for each difference.
+.It Fl s
+Print nothing and only return status.
+.El
+.Sh EXIT STATUS
+.Bl -tag -width Ds
+.It 0
+.Ar file1
+and
+.Ar file2
+are identical.
+.It 1
+.Ar file1
+and
+.Ar file2
+are different.
+.It > 1
+An error occurred.
+.El
+.Sh SEE ALSO
+.Xr comm 1 ,
+.Xr diff 1
+.Sh STANDARDS
+POSIX.1-2013.
+.Pp
+The "char" in the default result format has been replaced with "byte".