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

fusl/src/linux/prctl.c

Index: fusl/src/linux/prctl.c
diff --git a/fusl/src/linux/prctl.c b/fusl/src/linux/prctl.c
new file mode 100644
index 0000000000000000000000000000000000000000..19f4267cdeda4563fae0996b138cca04803746a4
--- /dev/null
+++ b/fusl/src/linux/prctl.c
@@ -0,0 +1,14 @@
+#include <sys/prctl.h>
+#include <stdarg.h>
+#include "syscall.h"
+
+int prctl(int op, ...)
+{
+	unsigned long x[4];
+	int i;
+	va_list ap;
+	va_start(ap, op);
+	for (i=0; i<4; i++) x[i] = va_arg(ap, unsigned long);
+	va_end(ap);
+	return syscall(SYS_prctl, op, x[0], x[1], x[2], x[3]);
+}