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/libutf/fputrune.c

@@ -0,0 +1,27 @@
+/* See LICENSE file for copyright and license details. */
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../utf.h"
+
+int
+fputrune(const Rune *r, FILE *fp)
+{
+	char buf[UTFmax];
+
+	return fwrite(buf, runetochar(buf, r), 1, fp);
+}
+
+int
+efputrune(const Rune *r, FILE *fp, const char *file)
+{
+	int ret;
+
+	if ((ret = fputrune(r, fp)) < 0) {
+		fprintf(stderr, "fputrune %s: %s\n", file, strerror(errno));
+		exit(1);
+	}
+	return ret;
+}