Fix window resize not always working

Change doresize to atomic_flag to prevent race condition

src/win/win.c

@@ -35,6 +35,7 @@
 #include <direct.h>
 #include <wchar.h>
 #include <io.h>
+#include <stdatomic.h>
 #define HAVE_STDARG_H
 #include <86box/86box.h>
 #include <86box/config.h>
@@ -550,12 +551,11 @@ main_thread(void *param)
 		// Sleep(1);
 
 	/* If needed, handle a screen resize. */
-	if (doresize && !video_fullscreen && !is_quit) {
+	if (!atomic_flag_test_and_set(&doresize) && !video_fullscreen && !is_quit) {
 		if (vid_resize & 2)
 			plat_resize(fixed_size_x, fixed_size_y);
 		else
 			plat_resize(scrnsz_x, scrnsz_y);
-		doresize = 0;
 	}
     }
 
@@ -1162,7 +1162,7 @@ plat_setfullscreen(int on)
     video_fullscreen &= 1;
     video_force_resize_set(1);
     if (!(on & 1))
-	doresize = 1;
+        atomic_flag_clear(&doresize);
 
     win_mouse_init();
 

src/win/win_specify_dim.c

@@ -133,7 +133,7 @@ SpecifyDimensionsDialogProcedure(HWND hdlg, UINT message, WPARAM wParam, LPARAM
 
 				scrnsz_x = fixed_size_x;
 				scrnsz_y = fixed_size_y;
-				doresize = 1;
+				atomic_flag_clear(&doresize);
 
 				GetWindowRect(hwndMain, &r);
 

src/win/win_ui.c

@@ -672,7 +672,7 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 
 				scrnsz_x = unscaled_size_x;
 				scrnsz_y = unscaled_size_y;
-				doresize = 1;
+				atomic_flag_clear(&doresize);
 				config_save();
 				break;
 
@@ -771,7 +771,7 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 				reset_screen_size();
 				device_force_redraw();
 				video_force_resize_set(1);
-				doresize = 1;
+				atomic_flag_clear(&doresize);
 				config_save();
 				break;
 
@@ -786,7 +786,7 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 			case IDM_VID_HIDPI:
 				dpi_scale = !dpi_scale;
 				CheckMenuItem(hmenu, IDM_VID_HIDPI, dpi_scale ? MF_CHECKED : MF_UNCHECKED);
-				doresize = 1;
+				atomic_flag_clear(&doresize);
 				config_save();
 				break;
 				
@@ -947,7 +947,7 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 			else
 				ResizeWindowByClientArea(hwndMain, temp_x, temp_y + sbar_height);
 		} else if (!user_resize)
-			doresize = 1;
+			atomic_flag_clear(&doresize);
 		break;
 
 	case WM_WINDOWPOSCHANGED:
@@ -992,13 +992,13 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 				if (temp_x != scrnsz_x || temp_y != scrnsz_y) {
 					scrnsz_x = temp_x;
 					scrnsz_y = temp_y;
-					doresize = 1;
+					atomic_flag_clear(&doresize);
 				}
 			} else {
 				if (rect.right != scrnsz_x || rect.bottom != scrnsz_y) {
 					scrnsz_x = rect.right;
 					scrnsz_y = rect.bottom;
-					doresize = 1;
+					atomic_flag_clear(&doresize);
 				}
 			}
 
@@ -1160,7 +1160,7 @@ MainWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 		/* If window is not resizable, then tell the main thread to
 		   resize it, as sometimes, moves can mess up the window size. */
 		if (!vid_resize)
-			doresize = 1;
+			atomic_flag_clear(&doresize);
 		break;
     }