Build config flags are either defined or undefined, never 0

This is for consistency with CMake build configuration

Also added SDL_VIDEO_RENDER_GPU to the non-CMake build configurations

src/render/software/SDL_blendfillrect.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "SDL_draw.h"
 #include "SDL_blendfillrect.h"

src/render/software/SDL_blendline.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "SDL_draw.h"
 #include "SDL_blendline.h"

src/render/software/SDL_blendpoint.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "SDL_draw.h"
 #include "SDL_blendpoint.h"

src/render/software/SDL_drawline.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "SDL_draw.h"
 #include "SDL_drawline.h"

src/render/software/SDL_drawpoint.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "SDL_draw.h"
 #include "SDL_drawpoint.h"

src/render/software/SDL_render_sw.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include "../SDL_sysrender.h"
 #include "SDL_render_sw_c.h"

src/render/software/SDL_rotate.c

@@ -30,7 +30,7 @@ Andreas Schiffler -- aschiffler at ferzkopp dot net
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #if defined(SDL_PLATFORM_WIN32) || defined(SDL_PLATFORM_GDK)
 #include "../../core/windows/SDL_windows.h"

src/render/software/SDL_triangle.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_VIDEO_RENDER_SW
+#ifdef SDL_VIDEO_RENDER_SW
 
 #include <limits.h>