lib/csu: Get rid of unused fptr typedef on amd64.

[arrowd]

Summary

Make i386 and riscv parts not use it.

Test Plan

make buildworld buildkernel passes on amd64. make tinderbox fails on
various arches even without these changes.

[kib]

The changes are fine.

Tinderbox usually kept in the good shape these days, it should not fail. Show both how do you run it, and what errors do you see.

[arrowd]

I simply do

cd /usr/src
make -j8 tinderbox

The process stops at random moments. The _.tinderbox.failed file contains

arm EFIKA_MX kernel failed, check _.arm.EFIKA_MX for details
arm ARMADA38X kernel failed, check _.arm.ARMADA38X for details
mips.mips64 buildworld failed, check _.mips.mips64.buildworld for details
arm ALPINE kernel failed, check _.arm.ALPINE for details
mips.mips buildworld failed, check _.mips.mips.buildworld for details
arm RPI-B kernel failed, check _.arm.RPI-B for details
powerpc.powerpc64 buildworld failed, check _.powerpc.powerpc64.buildworld for details
amd64.amd64 buildworld failed, check _.amd64.amd64.buildworld for details

and these lines are different each time. At the same time, make buildworld -j8 for amd64 works fine. When I inspect log files for each build, I don't see any errors, just normal compilation messages and then make stop:

...
--- .depend.invctrig_test ---
echo invctrig_test.full: /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libc.a /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libprivateatf-c.a /usr/obj/usr/src/amd64.amd64/tmp/usr/lib/libm.a >> .depend.invctrig_test
--- invctrig_test.o ---
cc -target x86_64-unknown-freebsd14.0 --sysroot=/usr/obj/usr/src/amd64.amd64/tmp -B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin  -O2 -pipe -fno-common   -DHAVE_FENV_H -I/usr/src/contrib/netbsd-tests/lib/libc/gen -D__HAVE_LONG_DOUBLE -fno-builtin -DLDBL_PREC=64 -fPIE

make[2]: stopped in /usr/src

Could it be that failure in one make branch stops compilation of others?

[kib]

Yes, it seems to be a recent regression in make. Do you build on HEAD or stable?

[arrowd]

In D31281#704617, @kib wrote:

Yes, it seems to be a recent regression in make. Do you build on HEAD or stable?

On ~month old CURRENT.

[kib]

So yes, this is definitely the make (1) regression in HEAD. I tried tinderboxing your patch on stable/13 machine, and everything went fine. Feel free to commit with 'Approved by: kib'.