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/libutil/human.c

@@ -0,0 +1,25 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "../util.h"
+
+char *
+humansize(off_t n)
+{
+	static char buf[16];
+	const char postfixes[] = "BKMGTPE";
+	double size;
+	int i;
+
+	for (size = n, i = 0; size >= 1024 && i < strlen(postfixes); i++)
+		size /= 1024;
+
+	if (!i)
+		snprintf(buf, sizeof(buf), "%ju", (uintmax_t)n);
+	else
+		snprintf(buf, sizeof(buf), "%.1f%c", size, postfixes[i]);
+
+	return buf;
+}