Preparing Texinfo development infrastructure:
  ./tp/maintain/regenerate_file_lists.pl
  (cd tp && ./maintain/regenerate_docstr.sh Makefile.docstr)
  (cd tp/tests && ../maintain/regenerate_cmd_tests.sh Makefile.onetst . -base 'formatting encoded nested_formats customization coverage layout' -tex_html 'tex_html' -other 'other')
  aclocal -I gnulib/m4 && autoconf && autoheader && automake -a -c
/opt/csw/share/aclocal/glib.m4:8: warning: underquoted definition of AM_PATH_GLIB
/opt/csw/share/aclocal/glib.m4:8:   run info Automake 'Extending aclocal'
/opt/csw/share/aclocal/glib.m4:8:   or see https://www.gnu.org/software/automake/manual/automake.html#Extending-aclocal
configure.ac:110: installing 'build-aux/config.guess'
configure.ac:110: installing 'build-aux/config.sub'
configure.ac:18: installing 'build-aux/install-sh'
configure.ac:18: installing 'build-aux/missing'
configure.ac:87: installing 'build-aux/tap-driver.sh'
parallel-tests: installing 'build-aux/test-driver'
doc/Makefile.am:18: installing 'build-aux/mdate-sh'
gnulib/lib/Makefile.am: installing 'build-aux/depcomp'
  (cd tp/Texinfo/XS && libtoolize  && AUTOPOINT=true autoreconf --force --verbose --install)
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: linking file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'gnulib/m4'.
libtoolize: linking file 'gnulib/m4/libtool.m4'
libtoolize: linking file 'gnulib/m4/ltoptions.m4'
libtoolize: linking file 'gnulib/m4/ltsugar.m4'
libtoolize: linking file 'gnulib/m4/ltversion.m4'
libtoolize: linking file 'gnulib/m4/lt~obsolete.m4'
autoreconf: Entering directory `.'
autoreconf: running: true --force
autoreconf: running: /opt/csw/bin/aclocal --force -I gnulib/m4
/opt/csw/share/aclocal/glib.m4:8: warning: underquoted definition of AM_PATH_GLIB
/opt/csw/share/aclocal/glib.m4:8:   run info Automake 'Extending aclocal'
/opt/csw/share/aclocal/glib.m4:8:   or see https://www.gnu.org/software/automake/manual/automake.html#Extending-aclocal
autoreconf: configure.ac: tracing
autoreconf: running: /opt/csw/bin/libtoolize --copy --force
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: copying file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'gnulib/m4'.
libtoolize: copying file 'gnulib/m4/libtool.m4'
libtoolize: copying file 'gnulib/m4/ltoptions.m4'
libtoolize: copying file 'gnulib/m4/ltsugar.m4'
libtoolize: copying file 'gnulib/m4/ltversion.m4'
libtoolize: copying file 'gnulib/m4/lt~obsolete.m4'
/opt/csw/share/aclocal/glib.m4:8: warning: underquoted definition of AM_PATH_GLIB
/opt/csw/share/aclocal/glib.m4:8:   run info Automake 'Extending aclocal'
/opt/csw/share/aclocal/glib.m4:8:   or see https://www.gnu.org/software/automake/manual/automake.html#Extending-aclocal
autoreconf: running: /opt/csw/bin/autoconf --force
autoreconf: running: /opt/csw/bin/autoheader --force
autoreconf: running: /opt/csw/bin/automake --add-missing --copy --force-missing
configure.ac:176: installing 'build-aux/config.guess'
configure.ac:176: installing 'build-aux/config.sub'
configure.ac:15: installing 'build-aux/install-sh'
configure.ac:15: installing 'build-aux/missing'
Makefile.am: installing 'build-aux/depcomp'
autoreconf: Leaving directory `.'

Now run configure with your desired options, for instance:
  ./configure CFLAGS='-g'