net/mpich: fix build with clang 19 on i386
In bug 276035 this was already handled once, but with clang 19 on i386
we get similar link errors:
ld: error: undefined reference: __addtf3 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined) ld: error: undefined reference: __gttf2 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined) ld: error: undefined reference: __lttf2 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined) ld: error: undefined reference: __multf3 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined) ld: error: undefined reference: __extendxftf2 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined) ld: error: undefined reference: __trunctfxf2 >>> referenced by lib/.libs/libmpi.so (disallowed by --no-allow-shlib-undefined)
Again the cause is that the mpich configure script detects partial
float128 support on i386 (i.e. the compile doesn't immediately choke on
defining variables of that type). It then enables HAVE_FLOAT128, which
leads to the above errors, because compiler-rt does not support float128
on i386.
PR: 281557
Approved by: laurent.chardon@gmail.com (maintainer)
MFH: 2024Q3
(cherry picked from commit 9d5e42894b39c428c6241efb1a053f7e571a6fee)