diff --git a/src/os_vms_conf.h b/src/os_vms_conf.h
index 275a2c1..deb7080 100644
--- a/src/os_vms_conf.h
+++ b/src/os_vms_conf.h
@@ -146,6 +146,8 @@
 #undef	HAVE_SYS_POLL_H
 #undef  HAVE_FCHDIR
 #undef  HAVE_LSTAT
+#undef  HAVE_STDINT_H
+#undef  HAVE_XOS_R_H
 
 // Hardware specific
 #ifdef  VAX
@@ -157,6 +159,10 @@
 #undef  HAVE_ISNAN
 #define HAVE_NO_LONG_LONG
 #define VIM_SIZEOF_LONG 4
+#define LONG_LONG_MIN  (-2147483647-1)                                                                                                    
+#define LONG_LONG_MAX  (2147483647)                                                                                                     
+#define ULONG_LONG_MAX (4294967295U)
+#undef  XTHREADS
 #else // AXP and IA64
 #define HAVE_GETTIMEOFDAY
 #define HAVE_USLEEP
@@ -164,7 +170,12 @@
 #define HAVE_STRINGS_H
 #define HAVE_SIGSETJMP
 #define HAVE_ISNAN
+#define HAVE_NO_LONG_LONG
 #define VIM_SIZEOF_LONG 8
+#define LONG_LONG_MIN  (-9223372036854775807-1)                                                                                                    
+#define LONG_LONG_MAX  (9223372036854775807)                                                                                                     
+#define ULONG_LONG_MAX (18446744073709551615U)
+#define XTHREADS
 #endif
 
 // Compiler specific
@@ -177,7 +188,7 @@
 #define BROKEN_LOCALE
 #undef  DYNAMIC_ICONV
 #undef	HAVE_STRFTIME
-#else
+#else   // DECC
 #define HAVE_SELECT
 #define HAVE_FCNTL_H
 #define HAVE_UNISTD_H 1
@@ -198,7 +209,10 @@
 
 // GUI support defines
 #if defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_GTK)
+#define X_INCLUDE_GRP_H             // To use getgrgid
+#define XUSE_MTSAFE_API
 #define HAVE_X11
+#define WANT_X11
 #ifdef HAVE_XPM
 #define HAVE_X11_XPM_H
 #endif