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

fusl/src/linux/ptrace.c

Index: fusl/src/linux/ptrace.c
diff --git a/fusl/src/linux/ptrace.c b/fusl/src/linux/ptrace.c
new file mode 100644
index 0000000000000000000000000000000000000000..83b8022beefa8afc9abeb19dfc7e9bac35d605e8
--- /dev/null
+++ b/fusl/src/linux/ptrace.c
@@ -0,0 +1,25 @@
+#include <sys/ptrace.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include "syscall.h"
+
+long ptrace(int req, ...)
+{
+	va_list ap;
+	pid_t pid;
+	void *addr, *data, *addr2;
+	long ret, result;
+
+	va_start(ap, req);
+	pid = va_arg(ap, pid_t);
+	addr = va_arg(ap, void *);
+	data = va_arg(ap, void *);
+	addr2 = va_arg(ap, void *);
+	va_end(ap);
+
+	if (req-1U < 3) data = &result;
+	ret = syscall(SYS_ptrace, req, pid, addr, data, addr2);
+
+	if (ret < 0 || req-1U >= 3) return ret;
+	return result;
+}