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

fusl/src/network/gethostbyname2_r.c

+#define _GNU_SOURCE
+
+#include <sys/socket.h>
+#include <netdb.h>
+#include <string.h>
+#include <netinet/in.h>
+#include <errno.h>
+#include <stdint.h>
+#include "lookup.h"
+
+int gethostbyname2_r(const char *name, int af,
+        struct hostent *h, char *buf, size_t buflen,
+        struct hostent **res, int *err)
+{
+        struct address addrs[MAXADDRS];
+        char canon[256];
+        int i, cnt;
+        size_t align, need;
+
+        *res = 0;
+        cnt = __lookup_name(addrs, canon, name, af, AI_CANONNAME);
+        if (cnt<0) switch (cnt) {
+        case EAI_NONAME:
+                *err = HOST_NOT_FOUND;
+                return ENOENT;
+        case EAI_AGAIN:
+                *err = TRY_AGAIN;
+                return EAGAIN;
+        default:
+        case EAI_FAIL:
+                *err = NO_RECOVERY;
+                return EBADMSG;
+        case EAI_MEMORY:
+        case EAI_SYSTEM:
+                *err = NO_RECOVERY;
+                return errno;
+        case 0:
+                break;
+        }
+
+        h->h_addrtype = af;
+        h->h_length = af==AF_INET6 ? 16 : 4;
+
+        /* Align buffer */
+        align = -(uintptr_t)buf & sizeof(char *)-1;
+
+        need = 4*sizeof(char *);
+        need += (cnt + 1) * (sizeof(char *) + h->h_length);
+        need += strlen(name)+1;
+        need += strlen(canon)+1;
+        need += align;
+
+        if (need > buflen) return ERANGE;
+
+        buf += align;
+        h->h_aliases = (void *)buf;
+        buf += 3*sizeof(char *);
+        h->h_addr_list = (void *)buf;
+        buf += (cnt+1)*sizeof(char *);
+
+        h->h_name = h->h_aliases[0] = buf;
+        strcpy(h->h_name, canon);
+        buf += strlen(h->h_name)+1;
+
+        if (strcmp(h->h_name, name)) {
+                h->h_aliases[1] = buf;
+                strcpy(h->h_aliases[1], name);
+                buf += strlen(h->h_aliases[1])+1;
+        } else h->h_aliases[1] = 0;
+
+        h->h_aliases[2] = 0;
+
+        for (i=0; i<cnt; i++) {
+                h->h_addr_list[i] = (void *)buf;
+                buf += h->h_length;
+                memcpy(h->h_addr_list[i], addrs[i].addr, h->h_length);
+        }
+        h->h_addr_list[i] = 0;
+
+        *res = h;
+        return 0;
+}