diff --git a/src/os_unix.h b/src/os_unix.h
index a7a0c841f1..e1c7deee1c 100644
--- a/src/os_unix.h
+++ b/src/os_unix.h
@@ -129,13 +129,6 @@
 
 // on some systems time.h should not be included together with sys/time.h
 #if !defined(HAVE_SYS_TIME_H) || defined(TIME_WITH_SYS_TIME)
-// Needed for strptime()
-# ifndef _XOPEN_SOURCE
-#  define _XOPEN_SOURCE
-# endif
-# ifndef __USE_XOPEN
-#  define __USE_XOPEN
-# endif
 # include <time.h>
 #endif
 #ifdef HAVE_SYS_TIME_H
diff --git a/src/version.c b/src/version.c
index 9b8a02fac1..9df71b8add 100644
--- a/src/version.c
+++ b/src/version.c
@@ -737,6 +737,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2344,
 /**/
     2343,
 /**/
diff --git a/src/vim.h b/src/vim.h
index 4d409d46fd..c53b1416f2 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -36,8 +36,21 @@
     Error: configure did not run properly.  Check auto/config.log.
 # endif
 
+# ifdef UNIX
+// Needed for strptime().  Needs to be done early, since header files can
+// include other header files and end up including time.h, where these symbols
+// matter for Vim.
+// 700 is needed for mkdtemp().
+#  ifndef _XOPEN_SOURCE
+#   define _XOPEN_SOURCE    700
+#  endif
+#  ifndef __USE_XOPEN
+#   define __USE_XOPEN
+#  endif
+# endif
+
 // for INT_MAX, LONG_MAX et al.
-#include <limits.h>
+# include <limits.h>
 
 /*
  * Cygwin may have fchdir() in a newer release, but in most versions it