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

fusl/src/mman/munmap.c

Index: fusl/src/mman/munmap.c
diff --git a/fusl/src/mman/munmap.c b/fusl/src/mman/munmap.c
new file mode 100644
index 0000000000000000000000000000000000000000..3f711ee50145bc6bf1ed905b1e310a63b32ace72
--- /dev/null
+++ b/fusl/src/mman/munmap.c
@@ -0,0 +1,14 @@
+#include <sys/mman.h>
+#include "syscall.h"
+#include "libc.h"
+
+static void dummy(void) { }
+weak_alias(dummy, __vm_wait);
+
+int __munmap(void *start, size_t len)
+{
+	__vm_wait();
+	return syscall(SYS_munmap, start, len);
+}
+
+weak_alias(__munmap, munmap);