Cleanup add brace (#6545)

* Add braces after if conditions

* More add braces after if conditions

* Add braces after while() conditions

* Fix compilation because of macro being modified

* Add braces to for loop

* Add braces after if/goto

* Move comments up

* Remove extra () in the 'return ...;' statements

* More remove extra () in the 'return ...;' statements

* More remove extra () in the 'return ...;' statements after merge

* Fix inconsistent patterns are xxx == NULL vs !xxx

* More "{}" for "if() break;"  and "if() continue;"

* More "{}" after if() short statement

* More "{}" after "if () return;" statement

* More fix inconsistent patterns are xxx == NULL vs !xxx

* Revert some modificaion on SDL_RLEaccel.c

* SDL_RLEaccel: no short statement

* Cleanup 'if' where the bracket is in a new line

* Cleanup 'while' where the bracket is in a new line

* Cleanup 'for' where the bracket is in a new line

* Cleanup 'else' where the bracket is in a new line

(cherry picked from commit 6a2200823c to reduce conflicts merging between SDL2 and SDL3)

test/testgesture.c

@@ -108,7 +108,7 @@ drawCircle(SDL_Surface *screen, float x, float y, float r, unsigned int c)
     for (ty = (float) -SDL_fabs(r); ty <= (float) SDL_fabs((int) r); ty++) {
         xr = (float) SDL_sqrt(r * r - ty * ty);
         if (r > 0) { /* r > 0 ==> filled circle */
-            for(tx = -xr + 0.5f; tx <= xr - 0.5f; tx++) {
+            for (tx = -xr + 0.5f; tx <= xr - 0.5f; tx++) {
                 setpix(screen, x + tx, y + ty, c);
             }
         } else {
@@ -132,7 +132,7 @@ DrawScreen(SDL_Window *window)
     SDL_Surface *screen = SDL_GetWindowSurface(window);
     int i;
 
-    if (!screen) {
+    if (screen == NULL) {
         return;
     }
 
@@ -272,7 +272,7 @@ loop(void)
 int main(int argc, char* argv[])
 {
     state = SDLTest_CommonCreateState(argv, SDL_INIT_VIDEO);
-    if (!state) {
+    if (state == NULL) {
         return 1;
     }