diff --git a/src/atomic/SDL_atomic.c b/src/atomic/SDL_atomic.c
index 0c8d91d0f5..061061661a 100644
--- a/src/atomic/SDL_atomic.c
+++ b/src/atomic/SDL_atomic.c
@@ -104,7 +104,7 @@ extern __inline int _SDL_xadd_watcom(volatile int *a, int v);
 #define EMULATE_CAS 1
 #endif
 
-#if EMULATE_CAS
+#ifdef EMULATE_CAS
 static SDL_SpinLock locks[32];
 
 static SDL_INLINE void enterLock(void *a)
@@ -136,7 +136,7 @@ SDL_AtomicCAS(SDL_AtomicInt *a, int oldval, int newval)
     return (SDL_bool)OSAtomicCompareAndSwap32Barrier(oldval, newval, &a->value);
 #elif defined(__SOLARIS__)
     return (SDL_bool)((int)atomic_cas_uint((volatile uint_t *)&a->value, (uint_t)oldval, (uint_t)newval) == oldval);
-#elif EMULATE_CAS
+#elif defined(EMULATE_CAS)
     SDL_bool retval = SDL_FALSE;
 
     enterLock(a);
@@ -167,7 +167,7 @@ SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
     return (SDL_bool)OSAtomicCompareAndSwap32Barrier((int32_t)oldval, (int32_t)newval, (int32_t *)a);
 #elif defined(__SOLARIS__)
     return (SDL_bool)(atomic_cas_ptr(a, oldval, newval) == oldval);
-#elif EMULATE_CAS
+#elif defined(EMULATE_CAS)
     SDL_bool retval = SDL_FALSE;
 
     enterLock(a);