Bugfix: Fix problems exposed by unit testing and perform cleanups.

Bugfix: Fix problems exposed by unit testing and perform cleanups.

f_capability_ambient_set() should not be testing for (!value_flag).

Te flags pointer test should be "flags" and not "*flags".

Explicitly cast capability to void * for cap_free().

Use "value" rather than "code" for "f_capability_value_t".

Expand out CAP_IS_SUPPORTED() and CAP_AMBIENT_SUPPORTED() to explicitly set F_true and F_false.
This is better than relying on the direct result of those macros.

Make sure f_type support "weak" compiler attributes.
Rename the compiler attributes to be more than just for visibility.

Correct the function ordering.