Add more gfx backend flags (available features)

backends/source/gfx_citro3d.cpp

@@ -141,6 +141,9 @@ void GfxCitro3D::SysInit() {
   PDLOG("GfxCitro3D::SysInit();");
   impl = new Impl();
   Flags |= PDGfxBackendFlags_FlipUV_Y;
+  Flags |= PDGfxBackendFlags_HasClipRect;
+  Flags |= PDGfxBackendFlags_ReqPow2;
+  Flags |= PDGfxBackendFlags_ApproxSDF;
   impl->pShaderRaw = Pica::AssembleCode(LIShaderCTR);
   impl->pCode = DVLB_ParseFile((uint32_t*)impl->pShaderRaw.data(),
                                impl->pShaderRaw.size());

backends/source/gfx_directx9.cpp

@@ -112,6 +112,7 @@ void GfxDirectX9::SysInit() {
     }
     if (psBlob) psBlob->Release();
     if (errBlob) errBlob->Release();
+    Flags |= PDGfxBackendFlags_HasClipRect;
   } else {
     PDERR(
         "GfxDirectX9::SysInit Error: pDevice is not set!\nYOu need to include "

backends/source/gfx_opengl2.cpp

@@ -73,6 +73,7 @@ void GfxOpenGL2::pSetupShaderAttribs(u32 shader) {
 }
 
 void GfxOpenGL2::SysInit() {
+  Flags |= PDGfxBackendFlags_HasClipRect;
   pShader = CreateShaderProgram(pVertCode, pFragCode);
   glUseProgram(pShader);
   glGenBuffers(1, &VBO);

backends/source/gfx_opengl3.cpp

@@ -11,6 +11,7 @@
 
 namespace PD {
 void GfxOpenGL3::SysInit() {
+  Flags |= PDGfxBackendFlags_HasClipRect;
   std::string vcode = SpirvHelper::SPV2GLSL(
       std::vector<unsigned int>(
           Shaders::VertexShader,