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/mktemp.c

@@ -0,0 +1,92 @@
+/* See LICENSE file for copyright and license details. */
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-dqtu] [-p directory] [template]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int dflag = 0, pflag = 0, qflag = 0, tflag = 0, uflag = 0, fd;
+	char *template = "tmp.XXXXXXXXXX", *tmpdir = "", *pdir,
+	     *p, path[PATH_MAX], tmp[PATH_MAX];
+	size_t len;
+
+	ARGBEGIN {
+	case 'd':
+		dflag = 1;
+		break;
+	case 'p':
+		pflag = 1;
+		pdir = EARGF(usage());
+		break;
+	case 'q':
+		qflag = 1;
+		break;
+	case 't':
+		tflag = 1;
+		break;
+	case 'u':
+		uflag = 1;
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc > 1)
+		usage();
+	else if (argc == 1)
+		template = argv[0];
+
+	if (!argc || pflag || tflag) {
+		if ((p = getenv("TMPDIR")))
+			tmpdir = p;
+		else if (pflag)
+			tmpdir = pdir;
+		else
+			tmpdir = "/tmp";
+	}
+
+	len = estrlcpy(path, tmpdir, sizeof(path));
+	if (path[0] && path[len - 1] != '/')
+		estrlcat(path, "/", sizeof(path));
+
+	estrlcpy(tmp, template, sizeof(tmp));
+	p = dirname(tmp);
+	if (!(p[0] == '.' && p[1] == '\0')) {
+		if (tflag && !pflag)
+			eprintf("template must not contain directory separators in -t mode\n");
+	}
+	estrlcat(path, template, sizeof(path));
+
+	if (dflag) {
+		if (!mkdtemp(path)) {
+			if (!qflag)
+				eprintf("mkdtemp %s:", path);
+			return 1;
+		}
+	} else {
+		if ((fd = mkstemp(path)) < 0) {
+			if (!qflag)
+				eprintf("mkstemp %s:", path);
+			return 1;
+		}
+		if (close(fd))
+			eprintf("close %s:", path);
+	}
+	if (uflag)
+		unlink(path);
+	puts(path);
+
+	efshut(stdout, "<stdout>");
+	return 0;
+}