Hi,

hypre fails to build in a test rebuild on at least amd64 and arm64 with
gcc-16/g++-16, but builds properly with gcc-15/g++-15. The severity of this
report will be raised before the forky release.

The full build log can be found at:
https://people.debian.org/~ema/gcc-16-rebuilds/output-1/hypre_arm64.build.xz

The last lines of the build log are at the end of this report.

To build with GCC 16, either set CC=gcc-16 CXX=g++-16 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t=experimental install g++

Common build failures include unused (but set) variables, array subscripts
partly outside array bounds, and new/dropped symbols in Debian symbols files.
For other C/C++ related build failures see the porting guide at
http://gcc.gnu.org/gcc-16/porting_to.html

Please only close this issue after double-checking that the package can be
built correctly with GCC 16.

Please do not reassign this bug to another package. If a fix in another package
is required, then file a bug for the other package (or clone), and mark this
bug as blocked by the bug in the other package.

[...]


ac_ct_CXX=''
ac_ct_FC=''
bindir='${exec_prefix}/bin'
build='aarch64-unknown-linux-gnu'
build_alias='aarch64-linux-gnu'
build_cpu='aarch64'
build_os='linux-gnu'
build_vendor='unknown'
datadir='${datarootdir}'
datarootdir='${prefix}/share'
docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
dvidir='${docdir}'
exec_prefix='NONE'
host='aarch64-unknown-linux-gnu'
host_alias='aarch64-unknown-linux-gnu'
host_cpu='aarch64'
host_os='linux-gnu'
host_vendor='unknown'
htmldir='${docdir}'
includedir='${prefix}/include'
infodir='${prefix}/share/info'
libdir='${prefix}/lib/aarch64-linux-gnu'
libexecdir='${exec_prefix}/libexec'
localedir='${datarootdir}/locale'
localstatedir='/var'
mandir='${prefix}/share/man'
oldincludedir='/usr/include'
pdfdir='${docdir}'
prefix='/build/reproducible-path/hypre-3.1.0/debian/tmp/usr'
program_transform_name='s,x,x,'
psdir='${docdir}'
runstatedir='/run'
sbindir='${exec_prefix}/sbin'
sharedstatedir='${prefix}/com'
sysconfdir='/etc'
target='aarch64-unknown-linux-gnu'
target_alias='aarch64-unknown-linux-gnu'
target_cpu='aarch64'
target_os='linux-gnu'
target_vendor='unknown'

## ----------- ##
## confdefs.h. ##
## ----------- ##

/* confdefs.h */
#define PACKAGE_NAME "hypre"
#define PACKAGE_TARNAME "hypre"
#define PACKAGE_VERSION "3.1.0"
#define PACKAGE_STRING "hypre 3.1.0"
#define PACKAGE_BUGREPORT ""
#define PACKAGE_URL ""
#define HYPRE_RELEASE_NAME "hypre"
#define HYPRE_RELEASE_VERSION "3.1.0"
#define HYPRE_RELEASE_NUMBER 30100
#define HYPRE_RELEASE_DATE "2026/01/23"
#define HYPRE_RELEASE_TIME "00:00:00"
#define HYPRE_RELEASE_BUGS "https://github.com/hypre-space/hypre/issues"
#define HYPRE_MAXDIM 3
#define HYPRE_FMANGLE 0
#define HYPRE_FMANGLE_BLAS 0
#define HYPRE_FMANGLE_LAPACK 2
#define HAVE_SUPERLU 1
#define HYPRE_USING_DSUPERLU 1

configure: exit 1
dh_auto_configure: error: cd src && ./configure --build=aarch64-linux-gnu --prefix=/usr --includedir=\${prefix}/include --mandir=\${prefix}/share/man --infodir=\${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-option-checking --disable-silent-rules --libdir=\${prefix}/lib/aarch64-linux-gnu --runstatedir=/run --disable-maintainer-mode --disable-dependency-tracking --enable-shared --with-superlu --with-superlu-include=/usr/include/superlu --with-superlu-lib=-lsuperlu --with-dsuperlu --with-dsuperlu-include=/usr/include/superlu-dist --with-dsuperlu-lib=-lsuperlu_dist --with-MPI-include=/usr/lib/aarch64-linux-gnu/openmpi/lib/../../fortran/gfortran-mod-16/openmpi --with-MPI-libs="mpi_usempif08 mpi_usempi_ignore_tkr mpi_mpifh mpi" --with-MPI-lib-dirs=/usr/lib/aarch64-linux-gnu/openmpi/lib --with-MPI-flags= --with-extra-flags= --with-blas=yes --with-blas-lib=-lblas --with-lapack=yes --with-lapack-lib=-llapack --with-fmangle-lapack=one-underscore --prefix=/build/reproducible-path/hypre-3.1.0/debian/tmp/usr returned exit code 1
make[1]: *** [debian/rules:107: override_dh_auto_configure] Error 25
make[1]: Leaving directory '/build/reproducible-path/hypre-3.1.0'
make: *** [debian/rules:25: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess failed with exit status 2