[3.11] gh-78469: Declare missing sethostname for Solaris 10 (GH-109447) (#110581)

Add OS version specific macro for Solaris: Py_SUNOS_VERSION.
(cherry picked from commit 3b1580af07)

Co-authored-by: Jakub Kulík <Kulikjak@gmail.com>

Modules/socketmodule.c

@@ -5534,8 +5534,9 @@ 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

@@ -3860,6 +3860,17 @@ 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 '.'`
+
+cat >>confdefs.h <<_ACEOF
+#define Py_SUNOS_VERSION $SUNOS_VERSION
+_ACEOF
+
+    fi
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: \"$MACHDEP\"" >&5
 $as_echo "\"$MACHDEP\"" >&6; }

configure.ac

@@ -582,6 +582,14 @@ 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")
 

pyconfig.h.in

@@ -1595,6 +1595,9 @@
 /* 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