How do you build a canonical 64-bit time_t i686 build today?

[Carlos O'Donell]

Adhemerval,

Recently I tried to build what I remembered being the canoncial
64-bit time_t and 64-bit file offset i686 build, but it failed
like this on Fedora 35 with gcc 11:

gcc -m32 -Wl,--build-id=none -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 init-first.c -c -std=gnu11 -fgnu89-inline  -g -O2 -march=i686 -Wl,--build-id=none -Wall -Wwrite-strings -Wundef -Werror -fmerge-all-constants -frounding-math -fno-stack-protector -fno-common -Wstrict-prototypes -Wold-style-definition -fmath-errno    -fPIC  -fno-stack-protector -DSTACK_PROTECTOR_LEVEL=0 -Wa,-mtune=i686  -fcf-protection   -ftls-model=initial-exec    -g -O2 -march=i686 -Wl,--build-id=none  -I../include -I/home/carlos/build/glibc-review-i686/csu  -I/home/carlos/build/glibc-review-i686  -I../sysdeps/unix/sysv/linux/i386/i686  -I../sysdeps/i386/i686/nptl  -I../sysdeps/unix/sysv/linux/i386  -I../sysdeps/unix/sysv/linux/x86/include -I../sysdeps/unix/sysv/linux/x86  -I../sysdeps/x86/nptl  -I../sysdeps/i386/nptl  -I../sysdeps/unix/sysv/linux/include -I../sysdeps/unix/sysv/linux  -I../sysdeps/nptl  -I../sysdeps/pthread  -I../sysdeps/gnu  -I../sysdeps/unix/inet  -I../sysdeps/unix/sysv  -I../sysdeps/unix/i386  -I../sysdeps/unix  -I../sysdeps/posix  -I../sysdeps/i386/i686/fpu/multiarch  -I../sysdeps/i386/i686/fpu  -I../sysdeps/i386/i686/multiarch  -I../sysdeps/i386/i686  -I../sysdeps/i386/fpu  -I../sysdeps/x86/fpu  -I../sysdeps/i386  -I../sysdeps/x86/include -I../sysdeps/x86  -I../sysdeps/wordsize-32  -I../sysdeps/ieee754/float128  -I../sysdeps/ieee754/ldbl-96/include -I../sysdeps/ieee754/ldbl-96  -I../sysdeps/ieee754/dbl-64  -I../sysdeps/ieee754/flt-32  -I../sysdeps/ieee754  -I../sysdeps/generic  -I.. -I../libio -I. -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/11/include -isystem /home/carlos/build/glibc-headers-review-i686/include -D_LIBC_REENTRANT -include /home/carlos/build/glibc-review-i686/libc-modules.h -DMODULE_NAME=libc -include ../include/libc-symbols.h  -DPIC -DSHARED     -DTOP_NAMESPACE=glibc -o /home/carlos/build/glibc-review-i686/csu/init-first.os -MD -MP -MF /home/carlos/build/glibc-review-i686/csu/init-first.os.dt -MT /home/carlos/build/glibc-review-i686/csu/init-first.os
In file included from ../sysdeps/nptl/pthread.h:23,
                 from ../include/pthread.h:1,
                 from ../sysdeps/unix/sysv/linux/x86/elision-conf.h:21,
                 from ../sysdeps/nptl/lowlevellock.h:23,
                 from ../nptl/descr.h:28,
                 from ../sysdeps/i386/nptl/tls.h:114,
                 from ../sysdeps/i386/i686/nptl/tls.h:32,
                 from ../sysdeps/unix/sysv/linux/i386/sysdep.h:26,
                 from init-first.c:23:
../include/time.h:21:1: error: ‘asm’ declaration ignored due to conflict with previous rename [-Werror=pragmas]
   21 | libc_hidden_proto (mktime)
      | ^~~~~~~~~~~~~~~~~
../include/time.h:22:1: error: ‘asm’ declaration ignored due to conflict with previous rename [-Werror=pragmas]
   22 | libc_hidden_proto (timelocal)
      | ^~~~~~~~~~~~~~~~~
../include/time.h:23:1: error: ‘asm’ declaration ignored due to conflict with previous rename [-Werror=pragmas]
   23 | libc_hidden_proto (localtime)
      | ^~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[2]: *** [../o-iterator.mk:9: /home/carlos/build/glibc-review-i686/csu/init-first.os] Error 1
make[2]: Leaving directory '/home/carlos/src/glibc-review/csu'
make[1]: *** [Makefile:483: csu/subdir_lib] Error 2
make[1]: Leaving directory '/home/carlos/src/glibc-review'
make: *** [Makefile:9: all] Error 2

I added -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 to my CC and CXX because 
they are ABI-affecting options that I don't want to be purged from other
options I pass down to the build.

What is the canonical way to do this build for testing?

Should we have a build-many-glibc's option for this configuration?

-- 
Cheers,
Carlos.