Fix build of llvm in Release mode for multi-configuration generators (Visual Studio and Xcode)

interpreter/CMakeLists.txt

@@ -155,7 +155,7 @@ if(builtin_llvm)
   # in that case we set the flags for all configurations to the
   # flags of the build type assigned to LLVM_BUILD_TYPE.
 
-  if(GENERATOR_IS_MULTI_CONFIG)
+  if(MSVC OR XCODE)
     string(TOUPPER ${LLVM_BUILD_TYPE} LLVM_BUILD_TYPE)
     set(LLVM_C_FLAGS ${CMAKE_C_FLAGS_${LLVM_BUILD_TYPE}})
     set(LLVM_CXX_FLAGS ${CMAKE_CXX_FLAGS_${LLVM_BUILD_TYPE}})