Use #ifdef/#ifndef instead of #if defined/#if \!defined

src/thread/generic/SDL_syscond.c

@@ -32,7 +32,7 @@
  * will be chosen at runtime), the function names need to be
  * suffixed
  */
-#if !defined(SDL_THREAD_GENERIC_COND_SUFFIX)
+#ifndef SDL_THREAD_GENERIC_COND_SUFFIX
 #define SDL_CreateCond_generic      SDL_CreateCond
 #define SDL_DestroyCond_generic     SDL_DestroyCond
 #define SDL_CondSignal_generic      SDL_CondSignal

src/thread/generic/SDL_sysmutex.c

@@ -72,7 +72,7 @@ void SDL_DestroyMutex(SDL_mutex *mutex)
 /* Lock the mutex */
 int SDL_LockMutex(SDL_mutex *mutex) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn't know about NULL mutexes */
 {
-#if defined(SDL_THREADS_DISABLED)
+#ifdef SDL_THREADS_DISABLED
     return 0;
 #else
     SDL_threadID this_thread;
@@ -101,7 +101,7 @@ int SDL_LockMutex(SDL_mutex *mutex) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn
 /* try Lock the mutex */
 int SDL_TryLockMutex(SDL_mutex *mutex)
 {
-#if defined(SDL_THREADS_DISABLED)
+#ifdef SDL_THREADS_DISABLED
     return 0;
 #else
     int retval = 0;
@@ -133,7 +133,7 @@ int SDL_TryLockMutex(SDL_mutex *mutex)
 /* Unlock the mutex */
 int SDL_UnlockMutex(SDL_mutex *mutex) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn't know about NULL mutexes */
 {
-#if defined(SDL_THREADS_DISABLED)
+#ifdef SDL_THREADS_DISABLED
     return 0;
 #else
     if (mutex == NULL) {

src/thread/generic/SDL_syssem.c

@@ -24,7 +24,7 @@
 
 #include "SDL_systhread_c.h"
 
-#if defined(SDL_THREADS_DISABLED)
+#ifdef SDL_THREADS_DISABLED
 
 SDL_sem *
 SDL_CreateSemaphore(Uint32 initial_value)