https://gcc.gnu.org/gcc-10/changes.html#c
> * GCC now defaults to `-fno-common`. As a result, global
> variable accesses are more efficient on various targets. In
> C, global variables with multiple tentative definitions now
> result in linker errors. With `-fcommon` such definitions are
> silently merged during linking.
* ext/win32ole/win32ole.c: use rb_sym2str when the result strings
will not be modified.
* ext/win32ole/win32ole_event.c: ditto.
* ext/win32ole/win32ole_record.c: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50311 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
use 0 for rb_data_type_t::reserved instead of NULL, since its type
may be changed in the future and possibly not a pointer type.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48662 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
