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

fusl/src/internal/fdpic_crt.h

+#include <stdint.h>
+
+__attribute__((__visibility__("hidden")))
+void *__fdpic_fixup(void *map, uintptr_t *a, uintptr_t *z)
+{
+        /* If map is a null pointer, the program was loaded by a
+         * non-FDPIC-aware ELF loader, and fixups are not needed,
+         * but the value for the GOT pointer is. */
+        if (!map) return (void *)z[-1];
+
+        struct {
+                unsigned short version, nsegs;
+                struct fdpic_loadseg {
+                        uintptr_t addr, p_vaddr, p_memsz;
+                } segs[];
+        } *lm = map;
+        int nsegs = lm->nsegs, rseg = 0, vseg = 0;
+        for (;;) {
+                while (*a-lm->segs[rseg].p_vaddr >= lm->segs[rseg].p_memsz)
+                        if (++rseg == nsegs) rseg = 0;
+                uintptr_t *r = (uintptr_t *)
+                        (*a + lm->segs[rseg].addr - lm->segs[rseg].p_vaddr);
+                if (++a == z) return r;
+                while (*r-lm->segs[vseg].p_vaddr >= lm->segs[vseg].p_memsz)
+                        if (++vseg == nsegs) vseg = 0;
+                *r += lm->segs[vseg].addr - lm->segs[vseg].p_vaddr;
+        }
+}