more typecasts to double to avoid 32-bit int overflows when computing memory usage

src/MISC/fix_gld.cpp

@@ -487,7 +487,7 @@ void FixGLD::reset_dt()
 
 double FixGLD::memory_usage()
 {
-  double bytes = atom->nmax*3*prony_terms*sizeof(double);
+  double bytes = (double)atom->nmax*3*prony_terms*sizeof(double);
   return bytes;
 }
 

src/MISC/fix_orient_bcc.cpp

@@ -596,7 +596,7 @@ int FixOrientBCC::compare(const void *pi, const void *pj)
 
 double FixOrientBCC::memory_usage()
 {
-  double bytes = nmax * sizeof(Nbr);
+  double bytes = (double)nmax * sizeof(Nbr);
   bytes += (double)2*nmax * sizeof(double);
   return bytes;
 }

src/MISC/fix_orient_fcc.cpp

@@ -594,7 +594,7 @@ int FixOrientFCC::compare(const void *pi, const void *pj)
 
 double FixOrientFCC::memory_usage()
 {
-  double bytes = nmax * sizeof(Nbr);
+  double bytes = (double)nmax * sizeof(Nbr);
   bytes += (double)2*nmax * sizeof(double);
   return bytes;
 }