Fixed failling FFT test when optimization is switched off.

tests/testFFT.c

@@ -28,7 +28,6 @@ int main() { return 0; }
 #else
 
 /* Some standard headers. */
-#include <fenv.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -41,9 +40,6 @@ int main() {
   unsigned long long cpufreq = 0;
   clocks_set_cpufreq(cpufreq);
 
-  /* Choke on FP-exceptions */
-  feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
-
   /* Make one particle */
   int nr_gparts = 1;
   struct gpart *gparts = NULL;