[Bug c/102989] Implement C2x's n2763 (_BitInt)

[joseph at codesourcery dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102989

--- Comment #10 from joseph at codesourcery dot com <joseph at codesourcery dot 
com> ---
N2775 (hopefully to be considered at the Jan/Feb 2022 WG14 meeting) is the 
proposal for constant suffixes.