The if-consteval branches in std::make_exception_ptr and
std::exception_ptr_cast use a try-catch block, which gives an error for
-fno-exceptions. Just make them return a null pointer at compile-time
when -fno-exceptions is used, because there's no way to get an active
exception with -fno-exceptions.
For both functions we have a runtime-only branch that depends on RTTI,
and a fallback using try-catch which works for runtime and consteval.
Rearrange both functions to express this logic more clearly.
Also adjust some formatting and whitespace elsewhere in the file.
libstdc++-v3/ChangeLog:
* libsupc++/exception_ptr.h (make_exception_ptr): Return null
for consteval when -fno-exceptions is used.
(exception_ptr_cast): Likewise. Allow consteval path to work
with -fno-rtti.
Reviewed-by: Jakub Jelinek <jakub@redhat.com>