FTBFS on arm64

partclone currently FTBFS on arm64:

make[1]: Entering directory `/build/buildd/partclone-0.2.51'
# Add here commands to configure the package.
cp /usr/share/misc/config.sub .
cp /usr/share/misc/config.guess .
autoreconf
automake: warnings are treated as errors
configure.ac:6: warning: The 'AM_PROG_MKDIR_P' macro is deprecated, and its use is discouraged.
configure.ac:6: You should use the Autoconf-provided 'AC_PROG_MKDIR_P' macro instead,
configure.ac:6: and use '$(MKDIR_P)' instead of '$(mkdir_p)'in your Makefile.am files.
src/Makefile.am:134: warning: compiling 'main.c' with per-target flags requires 'AM_PROG_CC_C_O' in 'configure.ac'
src/Makefile.am:19: warning: 'CFLAGS' is a user variable, you should not override it;
src/Makefile.am:19: use 'AM_CFLAGS' instead
src/Makefile.am:11: warning: 'LDFLAGS' is a user variable, you should not override it;
src/Makefile.am:11: use 'AM_LDFLAGS' instead
autoreconf: automake failed with exit status: 1
make[1]: *** [override_dh_auto_configure] Error 1
make[1]: Leaving directory `/build/buildd/partclone-0.2.51'
make: *** [build-arch] Error 2
dpkg-buildpackage: error: debian/rules build-arch gave error exit status 2