This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.
In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>. <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This change provides implementations for the mbrtoc8 and c8rtomb
functions adopted for C++20 via WG21 P0482R6 and for C2X via WG14
N2653. It also provides the char8_t typedef from WG14 N2653.
The mbrtoc8 and c8rtomb functions are declared in uchar.h in C2X
mode or when the _GNU_SOURCE macro or C++20 __cpp_char8_t feature
test macro is defined.
The char8_t typedef is declared in uchar.h in C2X mode or when the
_GNU_SOURCE macro is defined and the C++20 __cpp_char8_t feature
test macro is not defined (if __cpp_char8_t is defined, then char8_t
is a builtin type).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
