The purpose is to avoid using the `MRB_TT_CPTR` object.
The reasons are as follows:
- The `MRB_WORD_BOXING` setting involves object creation.
- If object creation fails, the `ary_set_t` data leaks memory.
refactored five functions to use mrb_ensure() instead of MRB_TRY/MRB_CATCH:
- ary_subtract_internal(): body/ensure pattern for set cleanup
- ary_union_internal(): body/ensure pattern for set cleanup
- ary_intersection_internal(): body/ensure pattern for set cleanup
- ary_intersect_p(): body/ensure pattern for set cleanup
- ary_uniq_bang(): body/ensure pattern for set cleanup
each function now uses a context struct containing set pointer and other
necessary data, with separate body and ensure functions that guarantee
cleanup on exception. this allows array-ext to compile as pure C without
requiring C++ compiler when enable_cxx_exception is set.
added mruby-error dependency to access mrb_ensure(). changed include
from throw.h to error.h. fix#6667.
Co-authored-by: Claude <noreply@anthropic.com>
dearblue