Fix sdl-haiku buildbot compiler warnings

src/main/beos/SDL_BApp.h

@@ -175,6 +175,9 @@ class SDL_BApp : public BApplication {
     		_PushBackWindow(win);
     		return i;
     	}
+
+    	/* TODO: error handling */
+    	return 0;
     }
 
     /* FIXME: Bad coding practice, but I can't include SDL_BWin.h here.  Is

src/video/SDL_bmp.c

@@ -49,7 +49,7 @@ SDL_Surface *
 SDL_LoadBMP_RW(SDL_RWops * src, int freesrc)
 {
     SDL_bool was_error;
-    long fp_offset;
+    long fp_offset = 0;
     int bmpPitch;
     int i, pad;
     SDL_Surface *surface;

src/video/bwindow/SDL_BWin.h

@@ -300,7 +300,6 @@ class SDL_BWin:public BDirectWindow
 
         switch (msg->what) {
         case B_MOUSE_MOVED:
-            where;
             int32 transit;
             if (msg->FindPoint("where", &where) == B_OK
                 && msg->FindInt32("be:transit", &transit) == B_OK) {
@@ -440,7 +439,6 @@ class SDL_BWin:public BDirectWindow
     			_MouseFocusEvent(false);
     		}
     	} else {
-    		static int x = 0, y = 0;
     		/* Change mouse focus */
     		if (!_mouse_focused) {
     			_MouseFocusEvent(true);

src/video/bwindow/SDL_bclipboard.cc

@@ -47,6 +47,7 @@ int BE_SetClipboardText(_THIS, const char *text) {
 		}
 		be_clipboard->Unlock();
 	}
+	return 0;
 }
 
 char *BE_GetClipboardText(_THIS) {

src/video/bwindow/SDL_bframebuffer.cc

@@ -115,7 +115,6 @@ int BE_UpdateWindowFramebuffer(_THIS, SDL_Window * window,
 
 int32 BE_DrawThread(void *data) {
 	SDL_BWin *bwin = (SDL_BWin*)data;
-	SDL_Window *window = _GetBeApp()->GetSDLWindow(bwin->GetID());
 
 	BScreen bscreen;
 	if(!bscreen.IsValid()) {

src/video/bwindow/SDL_bkeyboard.cc

@@ -158,7 +158,7 @@ void BE_InitOSKeymap() {
 }
 
 SDL_Scancode BE_GetScancodeFromBeKey(int32 bkey) {
-	if(bkey > 0 && bkey < SDL_TABLESIZE(keymap)) {
+	if(bkey > 0 && bkey < (int32)SDL_TABLESIZE(keymap)) {
 		return keymap[bkey];
 	} else {
 		return SDL_SCANCODE_UNKNOWN;

src/video/bwindow/SDL_bmodes.cc

@@ -184,6 +184,10 @@ int32 BE_BPPToSDLPxFormat(int32 bpp) {
 		return SDL_PIXELFORMAT_INDEX4LSB;
 		break;
 	}
+
+	/* May never get here, but safer and needed to shut up compiler */
+	SDL_SetError("Invalid bpp value");
+	return 0;       
 }
 
 static void _BDisplayModeToSdlDisplayMode(display_mode *bmode,
@@ -236,6 +240,7 @@ int BE_InitModes(_THIS) {
 	/* TODO: When Haiku supports multiple display screens, call
 	   _AddDisplayScreen() for each of them. */
 	_AddDisplay(&screen);
+	return 0;
 }
 
 int BE_QuitModes(_THIS) {

src/video/bwindow/SDL_bopengl.cc

@@ -59,6 +59,7 @@ int BE_GL_LoadLibrary(_THIS, const char *path)
 					SDL_arraysize(_this->gl_config.driver_path));
 		}
 	}
+	return 0;
 }
 
 void *BE_GL_GetProcAddress(_THIS, const char *proc)