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

fusl/src/unistd/lseek.c

Index: fusl/src/unistd/lseek.c
diff --git a/fusl/src/unistd/lseek.c b/fusl/src/unistd/lseek.c
new file mode 100644
index 0000000000000000000000000000000000000000..0a5ed392bc03c231208933ff3c2376bcfcb5f3b3
--- /dev/null
+++ b/fusl/src/unistd/lseek.c
@@ -0,0 +1,15 @@
+#include <unistd.h>
+#include "syscall.h"
+#include "libc.h"
+
+off_t lseek(int fd, off_t offset, int whence)
+{
+#ifdef SYS__llseek
+	off_t result;
+	return syscall(SYS__llseek, fd, offset>>32, offset, &result, whence) ? -1 : result;
+#else
+	return syscall(SYS_lseek, fd, offset, whence);
+#endif
+}
+
+LFS64(lseek);