dnl file : m4/diff.m4 dnl author : Boris Kolpackov <boris@codesynthesis.com> dnl copyright : Copyright (c) 2009-2011 Code Synthesis Tools CC dnl license : GNU GPL v2; see accompanying LICENSE file dnl dnl DIFF_TOOL dnl AC_DEFUN([DIFF_TOOL], [ diff_found=no AC_ARG_VAR([DIFF],[diff command]) AC_ARG_VAR([DIFFFLAGS],[diff flags]) AC_ARG_WITH( [diff], [AC_HELP_STRING([--with-diff=PATH],[path to the diff program])], [diff_path=${withval}], [diff_path=]) AC_MSG_CHECKING([for diff]) if test x"$DIFF" = x; then if test x"$diff_path" != x; then AS_SET_CATFILE([abs_diff_path], [$ac_pwd], [$diff_path]) DIFF="$abs_diff_path" else DIFF=diff fi fi cat >conftest.txt $DIFF conftest.txt conftest.txt 2>/dev/null 1>&2 if test x"$?" = x0; then AC_MSG_RESULT([$DIFF]) else AC_MSG_RESULT([no]) AC_MSG_ERROR([diff command is not found; consider setting the DIFF variable or using --with-diff=PATH]) fi AC_MSG_CHECKING([whether $DIFF accepts -u]) $DIFF -u conftest.txt conftest.txt 2>/dev/null 1>&2 if test x"$?" = x0; then AC_MSG_RESULT([yes]) DIFFFLAGS="$DIFFFLAGS -u" else AC_MSG_RESULT([no]) fi rm -f conftest.txt ])dnl