remove unused variable

src/library.cpp

@@ -317,8 +317,6 @@ void lammps_free(void *ptr)
 
 int lammps_extract_setting(void *ptr, char *name)
 {
-  LAMMPS *lmp = (LAMMPS *) ptr;
-
   if (strcmp(name,"bigint") == 0) return sizeof(bigint);
   if (strcmp(name,"tagint") == 0) return sizeof(tagint);
   if (strcmp(name,"imageint") == 0) return sizeof(imageint);