Issue #12852: Set _XOPEN_SOURCE to 700 to get POSIX 2008

configure: Set _XOPEN_SOURCE to 700, instead of 600, to get POSIX 2008
functions on OpenBSD (e.g. fdopendir).

Misc/NEWS

@@ -1209,6 +1209,9 @@ Library
 Build
 -----
 
+- Issue #12852: Set _XOPEN_SOURCE to 700, instead of 600, to get POSIX 2008
+  functions on OpenBSD (e.g. fdopendir).
+
 - Issue #11863: Remove support for legacy systems deprecated in Python 3.2
   (following PEP 11).  These systems are systems using Mach C Threads,
   SunOS lightweight processes, GNU pth threads and IRIX threads.

configure

@@ -3140,8 +3140,9 @@ esac
 
 if test $define_xopen_source = yes
 then
+  # X/Open 7, incorporating POSIX.1-2008
 
-$as_echo "#define _XOPEN_SOURCE 600" >>confdefs.h
+$as_echo "#define _XOPEN_SOURCE 700" >>confdefs.h
 
 
   # On Tru64 Unix 4.0F, defining _XOPEN_SOURCE also requires

configure.in

@@ -397,7 +397,8 @@ esac
 
 if test $define_xopen_source = yes
 then
-  AC_DEFINE(_XOPEN_SOURCE, 600, 
+  # X/Open 7, incorporating POSIX.1-2008
+  AC_DEFINE(_XOPEN_SOURCE, 700,
             Define to the level of X/Open that your system supports)
 
   # On Tru64 Unix 4.0F, defining _XOPEN_SOURCE also requires