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/cp.c

@@ -0,0 +1,63 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/stat.h>
+
+#include "fs.h"
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-afipv] [-R [-H | -L | -P]] source ... dest\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct stat st;
+
+	ARGBEGIN {
+	case 'i':
+		cp_iflag = 1;
+		break;
+	case 'a':
+		cp_follow = 'P';
+		cp_aflag = cp_pflag = cp_rflag = 1;
+		break;
+	case 'f':
+		cp_fflag = 1;
+		break;
+	case 'p':
+		cp_pflag = 1;
+		break;
+	case 'r':
+	case 'R':
+		cp_rflag = 1;
+		break;
+	case 'v':
+		cp_vflag = 1;
+		break;
+	case 'H':
+	case 'L':
+	case 'P':
+		cp_follow = ARGC();
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (argc < 2)
+		usage();
+
+	if (!cp_follow)
+		cp_follow = cp_rflag ? 'P' : 'L';
+
+	if (argc > 2) {
+		if (stat(argv[argc - 1], &st) < 0)
+			eprintf("stat %s:", argv[argc - 1]);
+		if (!S_ISDIR(st.st_mode))
+			eprintf("%s: not a directory\n", argv[argc - 1]);
+	}
+	enmasse(argc, argv, cp);
+
+	return fshut(stdout, "<stdout>") || cp_status;
+}