Enable D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY(#2572)

Enable -Gec flag when D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY bit is set
closes #2571

tools/clang/tools/d3dcomp/d3dcomp.cpp

@@ -80,8 +80,8 @@ HRESULT CompileFromBlob(IDxcBlobEncoding *pSource, LPCWSTR pSourceName,
     }
 
     std::vector<LPCWSTR> arguments;
-    // /Gec, /Ges Not implemented:
-    //if(Flags1 & D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY) arguments.push_back(L"/Gec");
+    if(Flags1 & D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY) arguments.push_back(L"/Gec");
+    // /Ges Not implemented:
     //if(Flags1 & D3DCOMPILE_ENABLE_STRICTNESS) arguments.push_back(L"/Ges");
     if(Flags1 & D3DCOMPILE_IEEE_STRICTNESS) arguments.push_back(L"/Gis");
     if(Flags1 & D3DCOMPILE_OPTIMIZATION_LEVEL2)

tools/clang/tools/dxlib-sample/lib_share_compile.cpp

@@ -270,9 +270,10 @@ HRESULT WINAPI DxilD3DCompile(LPCVOID pSrcData, SIZE_T SrcDataSize,
     }
 
     std::vector<LPCWSTR> arguments;
-    // /Gec, /Ges Not implemented:
-    // if(Flags1 & D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY)
-    // arguments.push_back(L"/Gec");  if(Flags1 & D3DCOMPILE_ENABLE_STRICTNESS)
+    if (Flags1 & D3DCOMPILE_ENABLE_BACKWARDS_COMPATIBILITY)
+      arguments.push_back(L"/Gec");
+    // /Ges Not implemented:
+    //if (Flags1 & D3DCOMPILE_ENABLE_STRICTNESS)
     // arguments.push_back(L"/Ges");
     if (Flags1 & D3DCOMPILE_IEEE_STRICTNESS)
       arguments.push_back(L"/Gis");