[Bug target/104208] -mlong-double-64 should override a previous -mabi=ibmlongdouble

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104208

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think the glibc problem is in a compiler defaulting to -mabi=ieeelongdouble
they want to use -mabi=ibmlongdouble -mlong-double-64 (because
-mabi=ibmlongdouble is added into CFLAGS everywhere early, and -mlong-double-64
is needed for a few TUs).
That wouldn't be diagnosed in the #c4 case, -mabi=ibmlongdouble is used while
-mlong-double-128 is in effect, so valid case.
-mlong-double-64 -mabi=ibmlongdouble
would be diagnosed though (-mabi=*double while -mlong-double-64 in effect).