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

fusl/src/mman/mprotect.c

Index: fusl/src/mman/mprotect.c
diff --git a/fusl/src/mman/mprotect.c b/fusl/src/mman/mprotect.c
new file mode 100644
index 0000000000000000000000000000000000000000..535787b9ec527bb12acbb80a53aadc4ab760c7b3
--- /dev/null
+++ b/fusl/src/mman/mprotect.c
@@ -0,0 +1,13 @@
+#include <sys/mman.h>
+#include "libc.h"
+#include "syscall.h"
+
+int __mprotect(void *addr, size_t len, int prot)
+{
+	size_t start, end;
+	start = (size_t)addr & -PAGE_SIZE;
+	end = (size_t)((char *)addr + len + PAGE_SIZE-1) & -PAGE_SIZE;
+	return syscall(SYS_mprotect, start, end-start, prot);
+}
+
+weak_alias(__mprotect, mprotect);