using GNU libc 2.27

[Paul Zimmermann]

       Hi,

I'd like to use GNU libc 2.27 with the CORE-MATH test suite. Some time ago
I got the following help from this list:

# to check the GNU libc 2.27, installed in say /tmp:
#     CORE_MATH_CHECK_STD=true CORE_MATH_LAUNCHER="/tmp/lib/ld-2.27.so --library-path /tmp/lib" LDFLAGS="-L /tmp/lib" ./check.sh --worst --rndn exp

I tried again and it fails (Debian Linux, with gcc 15.2.0) because MPFR needs
__isoc23_strtol:

zimmerma@coriandre:~/svn/core-math$ CFLAGS=-DCORE_MATH_NO_OPENMP OMP_NUM_THREADS=1 CORE_MATH_CHECK_STD=true CORE_MATH_LAUNCHER="$TMP/lib/ld-2.27.so --library-path $TMP/lib" LDFLAGS="-L $TMP/lib" ./check.sh --worst --rndn exp
/usr/bin/x86_64-linux-gnu-ld.bfd: check_worst.o: in function `readstdin':
check_worst_uni.c:(.text+0x202): undefined reference to `__isoc23_sscanf'
/usr/bin/x86_64-linux-gnu-ld.bfd: /usr/lib/gcc/x86_64-linux-gnu/15/../../../x86_64-linux-gnu/libmpfr.so: undefined reference to `__isoc23_strtol@GLIBC_2.38'
collect2: error: ld returned 1 exit status
gmake: *** [../support/Makefile.univariate:12: check_worst] Error 1

I recompiled GMP and MPFR with -std=c99, installed them in /tmp and tried
again, but now it seems the system ld needs __isoc23_strtol:

zimmerma@coriandre:~/svn/core-math$ CFLAGS="-I /tmp/include -std=c99 -DCORE_MATH_NO_OPENMP" OMP_NUM_THREADS=1 CORE_MATH_CHECK_STD=true CORE_MATH_LAUNCHER="$TMP/lib/ld-2.27.so --library-path $TMP/lib" LDFLAGS="-L /tmp/lib -L $TMP/lib" ./check.sh --worst --rndn exp
/usr/bin/x86_64-linux-gnu-ld.bfd: /tmp/lib/libgmp.so.10: undefined reference to `__isoc23_strtol@GLIBC_2.38'

Is there any hope to use GNU libc 2.27 with modern compilers?

(My goal is to check some math functions integrated from MathLibm and which
were correctly rounded.)

Paul