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

fusl/src/malloc/lite_malloc.c

Index: fusl/src/malloc/lite_malloc.c
diff --git a/fusl/src/malloc/lite_malloc.c b/fusl/src/malloc/lite_malloc.c
new file mode 100644
index 0000000000000000000000000000000000000000..a7e4a9f7b511bdbf2db4d5018e5088c19ed38570
--- /dev/null
+++ b/fusl/src/malloc/lite_malloc.c
@@ -0,0 +1,50 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <limits.h>
+#include <errno.h>
+#include "libc.h"
+
+#define ALIGN 16
+
+void *__expand_heap(size_t *);
+
+static void *__simple_malloc(size_t n)
+{
+	static char *cur, *end;
+	static volatile int lock[2];
+	size_t align=1, pad;
+	void *p;
+
+	if (!n) n++;
+	while (align<n && align<ALIGN)
+		align += align;
+
+	LOCK(lock);
+
+	pad = -(uintptr_t)cur & align-1;
+
+	if (n <= SIZE_MAX/2 + ALIGN) n += pad;
+
+	if (n > end-cur) {
+		size_t m = n;
+		char *new = __expand_heap(&m);
+		if (!new) {
+			UNLOCK(lock);
+			return 0;
+		}
+		if (new != end) {
+			cur = new;
+			n -= pad;
+			pad = 0;
+		}
+		end = new + m;
+	}
+
+	p = cur + pad;
+	cur += n;
+	UNLOCK(lock);
+	return p;
+}
+
+weak_alias(__simple_malloc, malloc);
+weak_alias(__simple_malloc, __malloc0);