gh-78469: Declare missing sethostname for Solaris 10 (#109447)

Add OS version specific macro for Solaris: Py_SUNOS_VERSION.

Author: kulikjak

Modules/socketmodule.c

@@ -5652,8 +5652,9 @@ socket_sethostname(PyObject *self, PyObject *args)
     Py_buffer buf;
     int res, flag = 0;
 
-#ifdef _AIX
-/* issue #18259, not declared in any useful header file */
+#if defined(_AIX) || (defined(__sun) && defined(__SVR4) && Py_SUNOS_VERSION <= 510)
+/* issue #18259, sethostname is not declared in any useful header file on AIX
+ * the same is true for Solaris 10 */
 extern int sethostname(const char *, size_t);
 #endif
 

configure

@@ -590,6 +590,14 @@ then
 	darwin*) MACHDEP="darwin";;
 	'')	MACHDEP="unknown";;
     esac
+
+    if test "$ac_sys_system" = "SunOS"; then
+	# For Solaris, there isn't an OS version specific macro defined
+	# in most compilers, so we define one here.
+	SUNOS_VERSION=`echo $ac_sys_release | sed -e 's!\.\([0-9]\)$!.0\1!g' | tr -d '.'`
+	AC_DEFINE_UNQUOTED([Py_SUNOS_VERSION], [$SUNOS_VERSION],
+	                   [The version of SunOS/Solaris as reported by `uname -r' without the dot.])
+    fi
 fi
 AC_MSG_RESULT(["$MACHDEP"])
 

configure.ac

@@ -1621,6 +1621,9 @@
 /* Define if you want to enable internal statistics gathering. */
 #undef Py_STATS
 
+/* The version of SunOS/Solaris as reported by `uname -r' without the dot. */
+#undef Py_SUNOS_VERSION
+
 /* Define if you want to enable tracing references for debugging purpose */
 #undef Py_TRACE_REFS