Fix remaining -Wundef warnings

Vaguely based on a patch from Thomas Zimmermann, but with a different
solution to RECURSIVE_MARSHAL_WRITE_TRACE, and additionally fixing
a build failure that only occurs when targeting Unix without libsystemd,
and another that occurs when targeting Windows.

Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=97357

dbus/dbus-marshal-recursive-util.c

@@ -35,6 +35,9 @@
 #define PRIx64 "I64x"
 #endif
 
+/** turn this on to get deluged in TypeWriter verbose spam */
+#define RECURSIVE_MARSHAL_WRITE_TRACE 0
+
 static void
 basic_value_zero (DBusBasicValue *value)
 {

dbus/dbus-sysdeps-win.c

@@ -2464,7 +2464,7 @@ static void dump_backtrace_for_thread (HANDLE hThread)
   sf.AddrFrame.Mode   = AddrModeFlat;
   sf.AddrPC.Offset    = context.Eip;
   sf.AddrPC.Mode      = AddrModeFlat;
-#elif _M_X64
+#elif defined(_M_X64)
   dwImageType         = IMAGE_FILE_MACHINE_AMD64;
   sf.AddrPC.Offset    = context.Rip;
   sf.AddrPC.Mode      = AddrModeFlat;
@@ -2472,7 +2472,7 @@ static void dump_backtrace_for_thread (HANDLE hThread)
   sf.AddrFrame.Mode   = AddrModeFlat;
   sf.AddrStack.Offset = context.Rsp;
   sf.AddrStack.Mode   = AddrModeFlat;
-#elif _M_IA64
+#elif defined(_M_IA64)
   dwImageType         = IMAGE_FILE_MACHINE_IA64;
   sf.AddrPC.Offset    = context.StIIP;
   sf.AddrPC.Mode      = AddrModeFlat;

dbus/dbus-userdb-util.c

@@ -29,7 +29,7 @@
 #include "dbus-protocol.h"
 #include <string.h>
 
-#if HAVE_SYSTEMD
+#ifdef HAVE_SYSTEMD
 #include <systemd/sd-login.h>
 #endif
 

test/test-segfault.c

@@ -44,7 +44,7 @@ main (int argc, char **argv)
   SetUnhandledExceptionFilter((LPTOP_LEVEL_EXCEPTION_FILTER)&exception_handler);
 #endif
 
-#if HAVE_SETRLIMIT
+#ifdef HAVE_SETRLIMIT
   /* No core dumps please, we know we crashed. */
   struct rlimit r = { 0, };