gdi32/tests: Use offsetof instead of sizeof on structs with VLA.

dlls/gdi32/tests/pen.c

@@ -153,7 +153,8 @@ static void test_logpen(void)
         if (pen[i].style == PS_NULL)
         {
             ok(hpen == GetStockObject(NULL_PEN), "hpen should be a stock NULL_PEN\n");
-            ok(size == sizeof(EXTLOGPEN), "GetObject returned %d, error %d\n", size, GetLastError());
+            ok(size == offsetof(EXTLOGPEN, elpStyleEntry[1]), "GetObject returned %d, error %d\n",
+                size, GetLastError());
             ok(elp.elpPenStyle == pen[i].ret_style, "expected %u, got %u\n", pen[i].ret_style, elp.elpPenStyle);
             ok(elp.elpWidth == 0, "expected 0, got %u\n", elp.elpWidth);
             ok(elp.elpColor == pen[i].ret_color, "expected %08x, got %08x\n", pen[i].ret_color, elp.elpColor);
@@ -275,7 +276,7 @@ static void test_logpen(void)
             memset(&unset_hatch, 0xb0, sizeof(unset_hatch));
             SetLastError(0xdeadbeef);
             size = GetObject(hpen, sizeof(elp), &elp);
-            ok(size == sizeof(EXTLOGPEN),
+            ok(size == offsetof(EXTLOGPEN, elpStyleEntry[1]),
                 "GetObject returned %d, error %d\n", size, GetLastError());
             ok(ext_pen->elpHatch == unset_hatch, "expected 0xb0b0b0b0, got %p\n", (void *)ext_pen->elpHatch);
             ok(ext_pen->elpNumEntries == 0xb0b0b0b0, "expected 0xb0b0b0b0, got %x\n", ext_pen->elpNumEntries);
@@ -385,11 +386,11 @@ test_geometric_pens:
         memset(elp_buffer, 0xb0, sizeof(elp_buffer));
         SetLastError(0xdeadbeef);
         /* buffer is too small for user styles */
-        size = GetObject(hpen, sizeof(EXTLOGPEN), elp_buffer);
+        size = GetObject(hpen, offsetof(EXTLOGPEN, elpStyleEntry[1]), elp_buffer);
         switch (pen[i].style)
         {
         case PS_NULL:
-            ok(size == sizeof(EXTLOGPEN),
+            ok(size == offsetof(EXTLOGPEN, elpStyleEntry[1]),
                 "GetObject returned %d, error %d\n", size, GetLastError());
             ok(ext_pen->elpHatch == 0, "expected 0, got %p\n", (void *)ext_pen->elpHatch);
             ok(ext_pen->elpNumEntries == 0, "expected 0, got %x\n", ext_pen->elpNumEntries);
@@ -568,7 +569,7 @@ static void test_ps_userstyle(void)
 
 static void test_brush_pens(void)
 {
-    char buffer[sizeof(EXTLOGPEN) + 15 * sizeof(DWORD)];
+    char buffer[offsetof(EXTLOGPEN, elpStyleEntry[16])];
     EXTLOGPEN *elp = (EXTLOGPEN *)buffer;
     LOGBRUSH lb;
     HPEN pen = 0;