die in an MPI-conformant way when running with MPI.

Former-commit-id: 600e09db0adf4742d48ed3ea66caaaec8a2d52cc

src/error.h

@@ -27,7 +27,7 @@
  */
 #ifdef WITH_MPI
     extern int engine_rank;
-    #define error(s, ...) { fprintf( stderr , "[%03i] %s:%s():%i: " s "\n" , engine_rank , __FILE__ , __FUNCTION__ , __LINE__ , ##__VA_ARGS__ ); abort(); }
+    #define error(s, ...) { fprintf( stderr , "[%03i] %s:%s():%i: " s "\n" , engine_rank , __FILE__ , __FUNCTION__ , __LINE__ , ##__VA_ARGS__ ); MPI_Abort(MPI_COMM_WORLD, -1); }
 #else
     #define error(s, ...) { fprintf( stderr , "%s:%s():%i: " s "\n" , __FILE__ , __FUNCTION__ , __LINE__ , ##__VA_ARGS__ ); abort(); }
 #endif

src/units.c

@@ -27,6 +27,9 @@
 #include <string.h>
 #include <stddef.h>
 #include <math.h>
+#ifdef WITH_MPI
+#include <mpi.h>
+#endif
 
 #include "const.h"
 #include "cycle.h"