When using the -fno-rtti option of the GCC style clang++, using typeid results in an error. The MSVC STL however kindly provides a define flag called _HAS_STATIC_RTTI, which either enables or disables uses of typeid throughout the STL. By default, if undefined, it is set to 1, enabling the use of typeid.
With this patch, _HAS_STATIC_RTTI is set to 0 when -fno-rtti is specified. This way various headers of the MSVC STL like functional can be consumed without compilation failures.
Differential Revision: https://reviews.llvm.org/D103771
Markus Böck