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/uname.c

@@ -0,0 +1,62 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/utsname.h>
+
+#include <stdio.h>
+
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-amnrsv]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct utsname u;
+	int mflag = 0, nflag = 0, rflag = 0, sflag = 0, vflag = 0;
+
+	ARGBEGIN {
+	case 'a':
+		mflag = nflag = rflag = sflag = vflag = 1;
+		break;
+	case 'm':
+		mflag = 1;
+		break;
+	case 'n':
+		nflag = 1;
+		break;
+	case 'r':
+		rflag = 1;
+		break;
+	case 's':
+		sflag = 1;
+		break;
+	case 'v':
+		vflag = 1;
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc)
+		usage();
+
+	if (uname(&u) < 0)
+		eprintf("uname:");
+
+	if (sflag || !(nflag || rflag || vflag || mflag))
+		putword(stdout, u.sysname);
+	if (nflag)
+		putword(stdout, u.nodename);
+	if (rflag)
+		putword(stdout, u.release);
+	if (vflag)
+		putword(stdout, u.version);
+	if (mflag)
+		putword(stdout, u.machine);
+	putchar('\n');
+
+	return fshut(stdout, "<stdout>");
+}