diff --git a/m4/ax_cc_for_build.m4 b/m4/ax_cc_for_build.m4
index c62ffadb..e49b7268 100644
--- a/m4/ax_cc_for_build.m4
+++ b/m4/ax_cc_for_build.m4
@@ -1,77 +1,77 @@
 # ===========================================================================
 #     https://www.gnu.org/software/autoconf-archive/ax_cc_for_build.html
 # ===========================================================================
 #
 # SYNOPSIS
 #
 #   AX_CC_FOR_BUILD
 #
 # DESCRIPTION
 #
 #   Find a build-time compiler. Sets CC_FOR_BUILD and EXEEXT_FOR_BUILD.
 #
 # LICENSE
 #
 #   Copyright (c) 2010 Reuben Thomas <rrt@sc3d.org>
 #   Copyright (c) 1999 Richard Henderson <rth@redhat.com>
 #
 #   This program is free software: you can redistribute it and/or modify it
 #   under the terms of the GNU General Public License as published by the
 #   Free Software Foundation, either version 3 of the License, or (at your
 #   option) any later version.
 #
 #   This program is distributed in the hope that it will be useful, but
 #   WITHOUT ANY WARRANTY; without even the implied warranty of
 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
 #   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
 #   scripts that are the output of Autoconf when processing the Macro. You
 #   need not follow the terms of the GNU General Public License when using
 #   or distributing such scripts, even though portions of the text of the
 #   Macro appear in them. The GNU General Public License (GPL) does govern
 #   all other use of the material that constitutes the Autoconf Macro.
 #
 #   This special exception to the GPL applies to versions of the Autoconf
 #   Macro released by the Autoconf Archive. When you make and distribute a
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
 #serial 3
 
 dnl Get a default for CC_FOR_BUILD to put into Makefile.
 AC_DEFUN([AX_CC_FOR_BUILD],
 [# Put a plausible default for CC_FOR_BUILD in Makefile.
 if test -z "$CC_FOR_BUILD"; then
   if test "x$cross_compiling" = "xno"; then
     CC_FOR_BUILD='$(CC)'
   else
     CC_FOR_BUILD=gcc
   fi
 fi
 AC_SUBST(CC_FOR_BUILD)
 # Also set EXEEXT_FOR_BUILD.
 if test "x$cross_compiling" = "xno"; then
   EXEEXT_FOR_BUILD='$(EXEEXT)'
 else
   AC_CACHE_CHECK([for build system executable suffix], bfd_cv_build_exeext,
     [rm -f conftest*
-     echo 'int main () { return 0; }' > conftest.c
+     echo 'int main (void) { return 0; }' > conftest.c
      bfd_cv_build_exeext=
      ${CC_FOR_BUILD} -o conftest conftest.c 1>&5 2>&5
      for file in conftest.*; do
        case $file in
        *.c | *.o | *.obj | *.ilk | *.pdb) ;;
        *) bfd_cv_build_exeext=`echo $file | sed -e s/conftest//` ;;
        esac
      done
      rm -f conftest*
      test x"${bfd_cv_build_exeext}" = x && bfd_cv_build_exeext=no])
   EXEEXT_FOR_BUILD=""
   test x"${bfd_cv_build_exeext}" != xno && EXEEXT_FOR_BUILD=${bfd_cv_build_exeext}
 fi
 AC_SUBST(EXEEXT_FOR_BUILD)])dnl
diff --git a/m4/noexecstack.m4 b/m4/noexecstack.m4
index ae0b26b8..85df0439 100644
--- a/m4/noexecstack.m4
+++ b/m4/noexecstack.m4
@@ -1,55 +1,55 @@
 # noexecstack.m4
 dnl Copyright (C) 1995-2006 Free Software Foundation, Inc.
 dnl
 dnl This library is free software; you can redistribute it and/or
 dnl modify it under the terms of the GNU Lesser General Public
 dnl License as published by the Free Software Foundation; either
 dnl version 2.1 of the License, or (at your option) any later version.
 dnl
 dnl This library is distributed in the hope that it will be useful,
 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 dnl Lesser General Public License for more details.
 dnl
 dnl You should have received a copy of the GNU Lesser General Public
 dnl License along with this library; if not, write to the Free Software
 dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 
 dnl Checks whether the stack can be marked nonexecutable by passing an
 dnl option to the C-compiler when acting on .s files.  Returns that
 dnl option in NOEXECSTACK_FLAGS.
 dnl This macro is adapted from one found in GLIBC-2.3.5.
 AC_DEFUN([CL_AS_NOEXECSTACK],[
 AC_REQUIRE([AC_PROG_CC])
 AC_REQUIRE([AM_PROG_AS])
 
 AC_MSG_CHECKING([whether non excutable stack support is requested])
 AC_ARG_ENABLE(noexecstack,
               AS_HELP_STRING([--disable-noexecstack],
                              [disable non executable stack support]),
               noexecstack_support=$enableval, noexecstack_support=yes)
 AC_MSG_RESULT($noexecstack_support)
 
 AC_CACHE_CHECK([whether assembler supports --noexecstack option],
 cl_cv_as_noexecstack, [dnl
   cat > conftest.c <<EOF
-void foo() {}
+void foo(void) {}
 EOF
   if AC_TRY_COMMAND([${CC} $CFLAGS $CPPFLAGS
                      -S -o conftest.s conftest.c >/dev/null]) \
      && grep .note.GNU-stack conftest.s >/dev/null \
      && AC_TRY_COMMAND([${CCAS} $CCASFLAGS $CPPFLAGS -Wa,--noexecstack
                        -c -o conftest.o conftest.s >/dev/null])
   then
     cl_cv_as_noexecstack=yes
   else
     cl_cv_as_noexecstack=no
   fi
   rm -f conftest*])
   if test "$noexecstack_support" = yes -a "$cl_cv_as_noexecstack" = yes; then
 	NOEXECSTACK_FLAGS="-Wa,--noexecstack"
   else
         NOEXECSTACK_FLAGS=
   fi
   AC_SUBST(NOEXECSTACK_FLAGS)
 ])