- Cabs2cil.is_boolean_result returns true if the expression is of type _Bool
- use standard result instead of custom expression for cast of a boolean to _Bool

glibc 2.35 (https://lists.gnu.org/archive/html/info-gnu/2022-02/msg00002.html)
defines macros __STDC_IEC_60559_BFP__ and __STDC_IEC_60559_COMPLEX__, which
must be ignored to avoid redefinition warnings during logic preprocessing.

  In order to fix merlin's locate definition

The former can be overloaded (via Printer.update_printer) by plug-ins who handle
mangled symbols, while the latter always prints the name as seen by Frama-C.

- always remove FC's internal attribute everywhere before deciding whether
  a cast is needed.
- ACSL and C decisions to cast are similar
- only unroll type for checking equality. If a cast is needed, keep
  typedef (if any) as target

The issue was introduced in 8fa891ec. Apparently
`Mergecil.union` has some interesting side effects even if one of the
field list is empty 

- lints some files