Add casts for stbtt alloc userdata

src/nuklear_font.c

@@ -192,7 +192,7 @@ nk_font_bake_pack(struct nk_font_baker *baker,
         it = config_iter;
         do {
             struct stbtt_fontinfo *font_info = &baker->build[i++].info;
-            font_info->userdata = alloc;
+            font_info->userdata = (void*)alloc;
 
             if (!stbtt_InitFont(font_info, (const unsigned char*)it->ttf_blob, stbtt_GetFontOffsetForIndex((const unsigned char*)it->ttf_blob, 0)))
                 return nk_false;
@@ -200,7 +200,7 @@ nk_font_bake_pack(struct nk_font_baker *baker,
     }
     *height = 0;
     *width = (total_glyph_count > 1000) ? 1024 : 512;
-    stbtt_PackBegin(&baker->spc, 0, (int)*width, (int)max_height, 0, 1, alloc);
+    stbtt_PackBegin(&baker->spc, 0, (int)*width, (int)max_height, 0, 1, (void*)alloc);
     {
         int input_i = 0;
         int range_n = 0;