MR: encapsulated user stuff

include/user.h

@@ -0,0 +1,16 @@
+#ifdef PENCIL_ASTAROTH
+
+  #include "../cparam.inc_c.h"
+  #define NGHOST nghost
+  #define STENCIL_ORDER (2*nghost)
+  #include "PC_moduleflags.h"
+  #define CONFIG_PATH
+  #define AC_MULTIGPU_ENABLED (false)
+  #ifdef DOUBLE_PRECISION 
+    #define AC_DOUBLE_PRECISION 1
+  #else
+    #define AC_DOUBLE_PRECISION 0
+  #endif
+  #define USER_PROVIDED
+#endif
+