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

fusl/src/malloc/memalign.c

+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+#include "libc.h"
+
+/* This function should work with most dlmalloc-like chunk bookkeeping
+ * systems, but it's only guaranteed to work with the native implementation
+ * used in this library. */
+
+void *__memalign(size_t align, size_t len)
+{
+        unsigned char *mem, *new, *end;
+        size_t header, footer;
+
+        if ((align & -align) != align) {
+                errno = EINVAL;
+                return NULL;
+        }
+
+        if (len > SIZE_MAX - align) {
+                errno = ENOMEM;
+                return NULL;
+        }
+
+        if (align <= 4*sizeof(size_t)) {
+                if (!(mem = malloc(len)))
+                        return NULL;
+                return mem;
+        }
+
+        if (!(mem = malloc(len + align-1)))
+                return NULL;
+
+        new = (void *)((uintptr_t)mem + align-1 & -align);
+        if (new == mem) return mem;
+
+        header = ((size_t *)mem)[-1];
+
+        if (!(header & 7)) {
+                ((size_t *)new)[-2] = ((size_t *)mem)[-2] + (new-mem);
+                ((size_t *)new)[-1] = ((size_t *)mem)[-1] - (new-mem);
+                return new;
+        }
+
+        end = mem + (header & -8);
+        footer = ((size_t *)end)[-2];
+
+        ((size_t *)mem)[-1] = header&7 | new-mem;
+        ((size_t *)new)[-2] = footer&7 | new-mem;
+        ((size_t *)new)[-1] = header&7 | end-new;
+        ((size_t *)end)[-2] = footer&7 | end-new;
+
+        free(mem);
+        return new;
+}
+
+weak_alias(__memalign, memalign);