Fix ODR violations

On a shared build, these symbols exist in both libglslang.so and
libSPIRV.so, leading to an ODR violation at runtime.

glslang/MachineIndependent/Initialize.h

@@ -107,6 +107,9 @@ protected:
     int dimMap[EsdNumDims];
 };
 
+// change this back to false if depending on textual spellings of texturing calls when consuming the AST
+// Using PureOperatorBuiltins=false is deprecated.
+constexpr bool PureOperatorBuiltins = true;
 } // end namespace glslang
 
 #endif // _INITIALIZE_INCLUDED_