Pre-declare the sump structure to avoid warnings when the whole dumping...

Pre-declare the sump structure to avoid warnings when the whole dumping mechanism is not available. Remove the '-malign-double' flag from the clang  compilation line.

m4/ax_cc_maxopt.m4

@@ -150,8 +150,7 @@ if test "$ac_test_CFLAGS" != "set"; then
      # default optimization flags for clang on all systems
      CFLAGS="-O3 -fomit-frame-pointer"
 
-     # -malign-double for x86 systems
-     AX_CHECK_COMPILE_FLAG(-malign-double, CFLAGS="$CFLAGS -malign-double")
+     # Always good optimisation to have
      AX_CHECK_COMPILE_FLAG(-fstrict-aliasing, CFLAGS="$CFLAGS -fstrict-aliasing")
 
      # note that we enable "unsafe" fp optimization with other compilers, too

src/logger.h

@@ -20,9 +20,11 @@
 #define SWIFT_LOGGER_H
 
 /* Includes. */
-#include "dump.h"
 #include "part.h"
 
+/* Forward declaration */
+struct dump;
+
 /**
  * Logger entries contain messages representing the particle data at a given
  * point in time during the simulation.