[PATCH 2/9] Use unsigned as base type for some enums

[Tom Tromey]

>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:

>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:
Simon> Doing a static assert like this:

Simon> +  gdb_static_assert (std::is_unsigned<underlying_type>::value);

Simon> would enforce it at compile time, which is preferable than finding it at
Simon> runtime.

Tom> I made this change.

This change turns out to be a bit too eager.  It requires changing all
the enums that are used by DEF_ENUM_FLAGS_TYPE; including
gcc_qualifiers, which is maintained in gcc (and theoretically at least
is C compatible) -- but operator~ is never actually used with these
other enums, so there isn't any UB to avoid.

However, moving the static assert to operator~ seems to work.

Tom