Add a "fork" of musl as //fusl.

fusl/src/temp/mkostemps.c

Index: fusl/src/temp/mkostemps.c
diff --git a/fusl/src/temp/mkostemps.c b/fusl/src/temp/mkostemps.c
new file mode 100644
index 0000000000000000000000000000000000000000..512b5f188a1fdb37dde4633e11becc0edee39767
--- /dev/null
+++ b/fusl/src/temp/mkostemps.c
@@ -0,0 +1,31 @@
+#define _BSD_SOURCE
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include "libc.h"
+
+char *__randname(char *);
+
+int __mkostemps(char *template, int len, int flags)
+{
+	size_t l = strlen(template);
+	if (l<6 || len>l-6 || memcmp(template+l-len-6, "XXXXXX", 6)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	flags -= flags & O_ACCMODE;
+	int fd, retries = 100;
+	do {
+		__randname(template+l-len-6);
+		if ((fd = open(template, flags | O_RDWR | O_CREAT | O_EXCL, 0600))>=0)
+			return fd;
+	} while (--retries && errno == EEXIST);
+
+	memcpy(template+l-len-6, "XXXXXX", 6);
+	return -1;
+}
+
+weak_alias(__mkostemps, mkostemps);
+weak_alias(__mkostemps, mkostemps64);