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/getconf.1

@@ -0,0 +1,57 @@
+.Dd October 8, 2015
+.Dt GETCONF 1
+.Os sbase
+.Sh NAME
+.Nm getconf
+.Nd get configuration values
+.Sh SYNOPSIS
+.Nm
+.Op Fl v Ar spec
+.Ar var
+.Ar [path]
+.Sh DESCRIPTION
+.Nm
+writes the value of the variable
+.Ar var
+to stdout.
+.sp
+If
+.Ar path
+is given,
+.Ar var
+is matched against configuration values from
+.Xr pathconf 3 .
+If
+.Ar path
+is not given,
+.Ar var
+is matched against configuration values from
+.Xr sysconf 3 ,
+.Xr confstr 3
+and limits.h (Minimum and Maximum).
+.sp
+If
+.Ar var
+is not defined,
+.Nm
+writes "undefined" to stdout.
+.Sh OPTIONS
+.Bl -tag -width Ds
+.It Fl v Ar spec
+Ignored.
+.El
+.Sh EXIT STATUS
+.Bl -tag -width Ds
+.It 0
+.Ar var
+was matched and its value written successfully.
+.It 1
+An error occured or
+.Ar var
+was invalid.
+.El
+.Sh STANDARDS
+POSIX.1-2013.
+Except for the
+.Op Fl v
+flag.