erts: Remove ERTS_SMP and USE_THREAD defines

This refactor was done using the unifdef tool like this:
    for file in $(find erts/ -name *.[ch]); do unifdef -t -f defile -o $file $file; done

where defile contained:
    #define ERTS_SMP 1
    #define USE_THREADS 1
    #define DDLL_SMP 1
    #define ERTS_HAVE_SMP_EMU 1
    #define SMP 1
    #define ERL_BITS_REENTRANT 1
    #define ERTS_USE_ASYNC_READY_Q 1
    #define FDBLOCK 1
    #undef ERTS_POLL_NEED_ASYNC_INTERRUPT_SUPPORT
    #define ERTS_POLL_ASYNC_INTERRUPT_SUPPORT 0
    #define ERTS_POLL_USE_WAKEUP_PIPE 1
    #define ERTS_POLL_USE_UPDATE_REQUESTS_QUEUE 1
    #undef ERTS_HAVE_PLAIN_EMU
    #undef ERTS_SIGNAL_STATE

1 files changed, 0 insertions, 2 deletions

diff --git a/erts/emulator/beam/erl_ptab.h b/erts/emulator/beam/erl_ptab.h
index fecfd96ab0..285d325cc4 100644
--- a/erts/emulator/beam/erl_ptab.h
+++ b/erts/emulator/beam/erl_ptab.h
@@ -387,10 +387,8 @@ ERTS_GLB_INLINE Sint erts_ptab_atmc_dec_test_refc(ErtsPTabElementCommon *ptab_el
 {
     erts_aint_t refc = erts_atomic_dec_read_relb(&ptab_el->refc.atmc);
     ERTS_SMP_LC_ASSERT(refc >= 0);
-#ifdef ERTS_SMP
     if (refc == 0)
 	ETHR_MEMBAR(ETHR_LoadLoad|ETHR_LoadStore);
-#endif
     return (Sint) refc;
 }