[dxbc] Only emit depth clamp in fragment shader if necessary

We don't need this if the depth clip extension is supported
by the driver.

src/dxbc/dxbc_compiler.cpp

@@ -6601,7 +6601,10 @@ namespace dxvk {
     
     this->emitOutputSetup();
     this->emitOutputMapping();
+
+    if (m_moduleInfo.options.useDepthClipWorkaround)
       this->emitOutputDepthClamp();
+    
     this->emitFunctionEnd();
   }
   

src/dxbc/dxbc_options.cpp

@@ -15,6 +15,8 @@ namespace dxvk {
     const DxvkDeviceFeatures& devFeatures = device->features();
     const DxvkDeviceInfo& devInfo = adapter->devicePropertiesExt();
     
+    useDepthClipWorkaround
+      = !devFeatures.extDepthClipEnable.depthClipEnable;
     useStorageImageReadWithoutFormat
       = devFeatures.core.features.shaderStorageImageReadWithoutFormat;
     useSubgroupOpsForEarlyDiscard

src/dxbc/dxbc_options.h

@@ -10,6 +10,10 @@ namespace dxvk {
     DxbcOptions();
     DxbcOptions(const Rc<DxvkDevice>& device, const D3D11Options& options);
 
+    // Clamp oDepth in fragment shaders if the depth
+    // clip device feature is not supported
+    bool useDepthClipWorkaround = false;
+
     /// Use the ShaderImageReadWithoutFormat capability.
     bool useStorageImageReadWithoutFormat = false;