allow build on hurd i386

This patch originates with:
https://salsa.debian.org/games-team/enet/-/commit/88648f10bd19d658167b0d303bef05e9e6144278

unix.c

@@ -148,7 +148,7 @@ 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__) || defined(__DragonFly__)
+#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__) || defined(__GNU__)
     gethostbyname_r (name, & hostData, buffer, sizeof (buffer), & hostEntry, & errnum);
 #else
     hostEntry = gethostbyname_r (name, & hostData, buffer, sizeof (buffer), & errnum);
@@ -220,7 +220,7 @@ enet_address_get_host (const ENetAddress * address, char * name, size_t nameLeng
 
     in.s_addr = address -> host;
 
-#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__) || defined(__GNU__)
     gethostbyaddr_r ((char *) & in, sizeof (struct in_addr), AF_INET, & hostData, buffer, sizeof (buffer), & hostEntry, & errnum);
 #else
     hostEntry = gethostbyaddr_r ((char *) & in, sizeof (struct in_addr), AF_INET, & hostData, buffer, sizeof (buffer), & errnum);