ignored type qualifiers

[graetz23]

Hi there,

having this in cloned Makefile:

make[1]: Entering directory '/home/chris/source/assembler/x64asm'
ccache g++ -Werror -Wextra -Wall -Wfatal-errors -pedantic -Wno-unused-parameter -Wno-reorder -Wignored-qualifiers -std=c++11 -fPIC -DNDEBUG -O3 -I./ -c src/r.cc -o src/r.o
src/r.cc: In member function ‘std::ostream& x64asm::R::write_att(std::ostream&) const’:
src/r.cc:221:12: error: type qualifiers ignored on cast result type [-Werror=ignored-qualifiers]
  221 |     return static_cast<const Rh* const>(this)->write_att(os);
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated due to -Wfatal-errors.

solving it by adding to Makefile ignore warning:

GCC=ccache .. -Wno-ignored-qualifiers ..

However, I think the const at:

case Type::RH:
  return static_cast<const R* const>(this)->write_att(os);
  break:

is not necessary, like:

case Type::RH:
  return static_cast<const R*>(this)->write_att(os);
  break:

and, therefore, may add some pull request.

best
Christian