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/xargs.1

@@ -0,0 +1,121 @@
+.Dd July 30, 2025
+.Dt XARGS 1
+.Os sbase
+.Sh NAME
+.Nm xargs
+.Nd construct argument lists and execute command
+.Sh SYNOPSIS
+.Nm
+.Op Fl 0prtx
+.Op Fl E Ar eofstr
+.Op Fl I Ar replstr
+.Op Fl n Ar num
+.Op Fl P Ar maxprocs
+.Op Fl s Ar num
+.Op Ar cmd Op Ar arg ...
+.Sh DESCRIPTION
+.Nm
+reads space, tab, newline and EOF delimited strings from stdin
+and executes the specified
+.Ar cmd
+with the strings as
+.Ar arguments .
+.Pp
+Any arguments specified on the command line are given to the command upon
+each invocation, followed by some number of the arguments read from
+stdin.
+The command is repeatedly executed one or more times until stdin is exhausted.
+.Pp
+Spaces, tabs and newlines may be embedded in arguments using single (`'')
+or double (`"') quotes or backslashes ('\e').
+Single quotes escape all non-single quote characters, excluding newlines, up
+to the matching single quote.
+Double quotes escape all non-double quote characters, excluding newlines, up
+to the matching double quote.
+Any single character, including newlines, may be escaped by a backslash.
+.Sh OPTIONS
+.Bl -tag -width Ds
+.It Fl 0
+Change
+.Nm
+to expect NUL ('\e0') characters as separators, instead of spaces
+and newlines.
+The quoting mechanisms described above are not performed.
+.It Fl E Ar eofstr
+Use
+.Ar eofstr
+as a logical EOF marker.
+.It Fl I Ar replstr
+Use
+.Ar replstr
+as the placeholder for the argument.
+Sets the arguments count to 1 per command line.
+It also implies the option x.
+.It Fl n Ar num
+Use at most
+.Ar num
+arguments per command line.
+.It Fl p
+Prompt mode: the user is asked whether to execute
+.Ar cmd
+at each invocation.
+Trace mode (-t) is turned on to write the command instance to be executed,
+followed by a prompt to standard error.
+An affirmative response read from
+.Pa /dev/tty
+executes the command, otherwise it is skipped.
+.It Fl P Ar maxprocs
+Parallel mode: run at most maxprocs invocations of
+.Ar cmd
+at once.
+.It Fl r
+Do not run the command if there are no arguments.
+Normally the command is executed at least once even if there are no arguments.
+.It Fl s Ar num
+Use at most
+.Ar num
+bytes per command line.
+.It Fl t
+Enable trace mode.
+Write the command line to stderr before executing it.
+.It Fl x
+Terminate if the command line exceeds the system limit or the number of bytes
+given with the
+.Op Fl s
+flag.
+.El
+.Sh EXIT STATUS
+.Nm
+exits with one of the following values:
+.Bl -tag -width Ds
+.It 0
+All invocations of
+.Ar cmd
+returned a zero exit status.
+.It 123
+One or more invocations of
+.Ar cmd
+returned a nonzero exit status.
+.It 124
+.Ar cmd
+exited with a 255 exit status.
+.It 125
+.Ar cmd
+was killed or stopped by a signal.
+.It 126
+.Ar cmd
+was found but could not be executed.
+.It 127
+.Ar cmd
+could not be found.
+.It 1
+Some other error occurred.
+.El
+.Sh STANDARDS
+POSIX.1-2013.
+.Pp
+The
+.Op Fl r
+and
+.Op Fl P
+flag is an extension to that specification.