[Bug bootstrap/67728] Build fails when cross-compiling with in-tree GMP and ISL

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67728

--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
GMP does, or did, select an ABI at configuration time that may not be the 
same as that used by default by the compiler used to build it.  For 
example, if building on an x86_64 processor it might select a 64-bit ABI 
even if you have configured GCC for a 32-bit host.  If your goal is to 
make multiple-precision computations as fast as possible, choosing the ABI 
for that purpose makes sense - but for GCC's uses the requirement is to 
choose the same ABI as for the selected host, even if that's slower than 
some other ABI available on the processor.