Fix -Wundef warnings due to disabling SDL_LIBC

src/SDL_log.c

@@ -28,7 +28,7 @@
 
 #include "SDL_log_c.h"
 
-#if HAVE_STDIO_H
+#ifdef HAVE_STDIO_H
 #include <stdio.h>
 #endif
 
@@ -484,7 +484,7 @@ static void SDLCALL SDL_LogOutput(void *userdata, int category, SDL_LogPriority
         }
     }
 #endif
-#if HAVE_STDIO_H && \
+#if defined(HAVE_STDIO_H) && \
     !(defined(__APPLE__) && (defined(SDL_VIDEO_DRIVER_COCOA) || defined(SDL_VIDEO_DRIVER_UIKIT)))
     (void)fprintf(stderr, "%s: %s\n", SDL_priority_prefixes[priority], message);
 #endif

src/audio/disk/SDL_diskaudio.c

@@ -24,7 +24,7 @@
 
 /* Output raw audio data to a file. */
 
-#if HAVE_STDIO_H
+#ifdef HAVE_STDIO_H
 #include <stdio.h>
 #endif
 

src/audio/sndio/SDL_sndioaudio.c

@@ -25,7 +25,7 @@
 
 /* OpenBSD sndio target */
 
-#if HAVE_STDIO_H
+#ifdef HAVE_STDIO_H
 #include <stdio.h>
 #endif
 

src/file/SDL_rwops.c

@@ -568,7 +568,7 @@ SDL_RWFromFile(const char *file, const char *mode)
     rwops->write = windows_file_write;
     rwops->close = windows_file_close;
     rwops->type = SDL_RWOPS_WINFILE;
-#elif HAVE_STDIO_H
+#elif defined(HAVE_STDIO_H)
     {
 #if defined(__APPLE__) && !SDL_FILE_DISABLED // TODO: add dummy?
         FILE *fp = SDL_OpenFPFromBundleOrFallback(file, mode);

test/testevdev.c

@@ -20,6 +20,7 @@
 #ifdef SDL_DYNAMIC_API
 #undef SDL_DYNAMIC_API
 #endif
+#define SDL_DYNAMIC_API 0
 
 #include "../src/SDL_internal.h"
 

test/testnative.h

@@ -20,6 +20,7 @@
 #ifdef SDL_DYNAMIC_API
 #undef SDL_DYNAMIC_API
 #endif
+#define SDL_DYNAMIC_API 0
 
 #include "../src/SDL_internal.h"