xrRenderPC_GL: Add platform-specific delimiter to shader path

Author: Zegeri

src/Layers/xrRenderPC_GL/rgl.h

@@ -302,7 +302,7 @@ class CRender : public D3DXRenderBase
 
     // Information
     void DumpStatistics(class IGameFont& font, class IPerformanceAlert* alert) override;
-    LPCSTR getShaderPath() override { return "gl\\"; }
+    LPCSTR getShaderPath() override { return "gl" DELIMITER; }
     virtual ref_shader getShader(int id);
     IRender_Sector* getSector(int id) override;
     IRenderVisual* getVisual(int id) override;