Matej provides me a link to the build logs on IRC:

It's GCC 9.1.1 (gcc9-9.1.1+r271393-1.2)

The compilation uses PGO and LTO.

./configure --host=x86_64-suse-linux-gnu --build=x86_64-suse-linux-gnu --program-prefix= --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/lib --localstatedir=/var --sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info --disable-dependency-tracking --docdir=/usr/share/doc/packages/python --enable-ipv6 --enable-shared --with-ensurepip=no --with-system-ffi --with-system-expat --with-lto --enable-optimizations --enable-loadable-sqlite-extensions

[   44s] configure: WARNING: unrecognized options: --disable-dependency-tracking, --disable-dependency-tracking

--

I'm unable to reproduce the issue on Fedora 30 using GCC 9.1.1:

$ ./configure --host=x86_64-suse-linux-gnu --build=x86_64-suse-linux-gnu --program-prefix= --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/lib --localstatedir=/var --sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info --disable-dependency-tracking --docdir=/usr/share/doc/packages/python --enable-ipv6 --enable-shared --with-ensurepip=no --with-system-ffi --with-system-expat --with-lto --enable-optimizations --enable-loadable-sqlite-extensions
...
$ vim Makefile
# replace "PROFILE_TASK=..." with "PROFILE_TASK=-c pass", just to make compilation faster ;-)
$ make
...
$ LD_LIBRARY_PATH=$PWD ./python -m test -v test_capi
...
Tests result: SUCCESS