gethostbyname_r update.

* gethostbyname_r is now the 6 arg version.
* Make enet use the right code path (this should be upstreamed).
* Add a compat header to make these declarations visible to all without
  extra compilation flags.

src/library.js

@@ -7480,12 +7480,13 @@ LibraryManager.library = {
   },
 
   gethostbyname_r__deps: ['gethostbyname'],
-  gethostbyname_r: function(name, ret, buf, buflen, err) {
+  gethostbyname_r: function(name, ret, buf, buflen, out, err) {
     var data = _gethostbyname(name);
     _memcpy(ret, data, ___hostent_struct_layout.__size__);
     _free(data);
     {{{ makeSetValue('err', '0', '0', 'i32') }}};
-    return ret;
+    {{{ makeSetValue('out', '0', 'ret', '*') }}};
+    return 0;
   },
 
   getaddrinfo__deps: ['$Sockets', '$DNS', '_addrinfo_layout', '_inet_pton4_raw', '_inet_ntop4_raw', '_inet_pton6_raw', '_inet_ntop6_raw', '_write_sockaddr', 'htonl'],

system/include/compat/netdb.h

@@ -0,0 +1,22 @@
+#ifndef _COMPAT_NETDB_H_
+#define _COMPAT_NETDB_H_
+
+#include_next <netdb.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The musl includes only define these things for old sources or
+   when certain flags are activated. We want these available
+   all of the time for now. */
+struct hostent *gethostbyname (const char *);
+struct hostent *gethostbyaddr (const void *, socklen_t, int);
+
+int gethostbyname_r(const char *, struct hostent *, char *, size_t, struct hostent **, int *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _COMPAT_NETDB_H_ */

tests/enet/unix.c

@@ -80,7 +80,7 @@ enet_address_set_host (ENetAddress * address, const char * name)
     char buffer [2048];
     int errnum;
 
-#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__EMSCRIPTEN__)
     gethostbyname_r (name, & hostData, buffer, sizeof (buffer), & hostEntry, & errnum);
 #else
     hostEntry = gethostbyname_r (name, & hostData, buffer, sizeof (buffer), & errnum);

tests/sockets/test_gethostbyname.c

@@ -13,12 +13,17 @@
 
 int main() {
   char str[INET_ADDRSTRLEN];
+  struct hostent *host = NULL;
+  struct hostent hostData;
   struct in_addr addr;
   const char *res;
+  char buffer[2048];
   int err;
   
-  // resolve the hostname ot an actual address
-  struct hostent *host = gethostbyname("slashdot.org");
+  // gethostbyname_r calls the same stuff as gethostbyname, so we'll test the
+  // more complicated one.
+  // resolve the hostname to an actual address
+  gethostbyname_r("slashdot.org", &hostData, buffer, sizeof(buffer), &host, &err);
   assert(host->h_addrtype == AF_INET);
   assert(host->h_length == sizeof(uint32_t));