Build error. Variable name is typename.

A heads up. Godot from github master branch (3.1.alpha.custom_build.89abfd4).

godot.x11.tools.64.llvm --gdnative-generate-json-api generates a function as bool handles_type(const String typename); but this will generate a build error because of typename.
error: expected nested-name-specifier before ')' token bool handles_type(const String typename);

godot::api->godot_string_operator_index has changed return type from wchar_t * to const wchar_t * (I think) which gives a const to non-const error in String.hpp:106
error: binding value of type 'const wchar_t' to reference to type 'wchar_t' drops 'const' qualifier