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/fshut.c

@@ -0,0 +1,43 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../util.h"
+
+int
+fshut(FILE *fp, const char *fname)
+{
+	int ret = 0;
+
+	/* fflush() is undefined for input streams by ISO C,
+	 * but not POSIX 2008 if you ignore ISO C overrides.
+	 * Leave it unchecked and rely on the following
+	 * functions to detect errors.
+	 */
+	fflush(fp);
+
+	if (ferror(fp) && !ret) {
+		weprintf("ferror %s:", fname);
+		ret = 1;
+	}
+
+	if (fclose(fp) && !ret) {
+		weprintf("fclose %s:", fname);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+void
+enfshut(int status, FILE *fp, const char *fname)
+{
+	if (fshut(fp, fname))
+		exit(status);
+}
+
+void
+efshut(FILE *fp, const char *fname)
+{
+	enfshut(1, fp, fname);
+}