[Bug target/77924] -mfloat128-type change broke AIX

[meissner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77924

--- Comment #1 from Michael Meissner <meissner at gcc dot gnu.org> ---
Created attachment 39784
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39784&action=edit
Proposed patch to fix the problem

This patch should only create the __ibm128 type when long double == IEEE and
long double size is 128 bits, so it should allow AIX to build (AIX long double
is 64-bits).