Reinstate missing pointer indirection for external gravity dependencies that...

Reinstate missing pointer indirection for external gravity dependencies that had disappeared in merge.

src/engine.c

@@ -2086,7 +2086,7 @@ static inline void engine_make_external_gravity_dependencies(
     struct scheduler *sched, struct task *gravity, struct cell *c) {
 
   /* init --> external gravity --> kick */
-  scheduler_addunlock(sched, c->drift_gpart, gravity);
+  scheduler_addunlock(sched, c->super->drift_gpart, gravity);
   scheduler_addunlock(sched, gravity, c->super->kick2);
 }
 

src/swift.h

@@ -35,6 +35,7 @@
 #include "engine.h"
 #include "error.h"
 #include "gravity.h"
+#include "gravity_derivatives.h"
 #include "gravity_properties.h"
 #include "hydro.h"
 #include "hydro_properties.h"

tests/testGravityDerivatives.c

@@ -930,9 +930,6 @@ int main() {
   unsigned long long cpufreq = 0;
   clocks_set_cpufreq(cpufreq);
 
-  /* Choke on FP-exceptions */
-  feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
-
   /* Relative tolerance */
   const double tol = 1e-4;