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

include/SDL3/SDL_stdinc.h

@@ -37,8 +37,8 @@
 #include <stdint.h>
 #include <wchar.h>
 
-#if !defined(alloca)
-# if defined(HAVE_ALLOCA_H)
+#ifndef alloca
+# ifdef HAVE_ALLOCA_H
 #  include <alloca.h>
 # elif defined(__GNUC__)
 #  define alloca __builtin_alloca
@@ -309,7 +309,7 @@ typedef uint64_t Uint64;
 #define SDL_PRINTF_FORMAT_STRING
 #define SDL_SCANF_FORMAT_STRING
 #endif
-#if defined(__GNUC__)
+#ifdef __GNUC__
 #define SDL_PRINTF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __printf__, fmtargnumber, fmtargnumber+1 )))
 #define SDL_SCANF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __scanf__, fmtargnumber, fmtargnumber+1 )))
 #else
@@ -319,7 +319,7 @@ typedef uint64_t Uint64;
 #endif /* SDL_DISABLE_ANALYZE_MACROS */
 
 #ifndef SDL_COMPILE_TIME_ASSERT
-#if defined(__cplusplus)
+#ifdef __cplusplus
 #if (__cplusplus >= 201103L)
 #define SDL_COMPILE_TIME_ASSERT(name, x)  static_assert(x, #x)
 #endif