File dialog improvements

- Add a globally-accessible function to handle the parsing of filter extensions
- Remove the ability of putting the wildcard ('*') among other patterns; it's either a list of patterns or a single '*' now
- Add a hint to select between portals and Zenity on Unix

VisualC-WinRT/SDL-UWP.vcxproj

@@ -315,6 +315,7 @@
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">NotUsing</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">NotUsing</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="..\src\dialog\SDL_dialog_utils.c" />
     <ClCompile Include="..\src\events\SDL_clipboardevents.c" />
     <ClCompile Include="..\src\events\SDL_displayevents.c" />
     <ClCompile Include="..\src\events\SDL_dropevents.c" />

VisualC-WinRT/SDL-UWP.vcxproj.filters

@@ -31,6 +31,9 @@
     <Filter Include="time\windows">
       <UniqueIdentifier>{0000012051ca8361c8e1013aee1d0000}</UniqueIdentifier>
     </Filter>
+    <Filter Include="dialog">
+      <UniqueIdentifier>{0000c99bfadbbcb05a474a8472910000}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\include\SDL3\SDL_begin_code.h">
@@ -567,6 +570,9 @@
     <ClCompile Include="..\src\cpuinfo\SDL_cpuinfo.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\dialog\SDL_dialog_utils.c">
+      <Filter>dialog</Filter>
+    </ClCompile>
     <ClCompile Include="..\src\dynapi\SDL_dynapi.c">
       <Filter>Source Files</Filter>
     </ClCompile>