Put back __osf__ support for gethostbyname_r(); the real bug was that

it was being used even without threads.  This of course might be an
all-platform problem so now we only use the _r variant when we are
using threads.

Modules/socketmodule.c

@@ -91,8 +91,12 @@ Socket methods:
 #undef HAVE_GETHOSTBYNAME_R_5_ARG
 #undef HAVE_GETHOSTBYNAME_R_6_ARG
 
+#ifndef WITH_THREAD
+#undef HAVE_GETHOSTBYNAME_R
+#endif
+
 #ifdef HAVE_GETHOSTBYNAME_R
-#if defined(_AIX)
+#if defined(_AIX) || defined(__osf__)
 #define HAVE_GETHOSTBYNAME_R_3_ARG
 #elif defined(__sun__) || defined(__sgi)
 #define HAVE_GETHOSTBYNAME_R_5_ARG