Bug in AC_CHECK_PROGS ?

[Philipp Thomas]

Environment:
         openSUSE 11.4
         autoconf 2.68
         automake 1.11.1

The part below in configure.ac of gcal 3.6 is failing and I don't see where the
error could be. Even running 'autoreconf -fi' and thus regenerating
aclocal.m4 und configure won't change anything. 

AC_CHECK_PROGS is set to 

${SHELL} /abuild/pth/gcal/gcal-3.6/build-aux/missing --run makeinfo

If I substitute ac_cv_prog_MAKEINFO with makeinfo in the call to set
makeinfo_version the code works as expected.

dnl
dnl Checks for makeinfo.
dnl
AC_CHECK_PROGS(MAKEINFO, gmakeinfo gnumakeinfo makeinfo)

if test -z "$ac_cv_prog_MAKEINFO"; then
  AC_MSG_RESULT()
  AC_MSG_WARN(no automatic recreation of HTML and Info documentation files!)
  AC_MSG_WARN(Makefile targets *html* and *info* will never be executed.)
  AC_MSG_RESULT()
else
  AC_MSG_CHECKING(for makeinfo version)
  changequote(<<, >>)dnl
  dnl
  dnl Gcal needs `makeinfo' from GNU Texinfo 3.12t minimum,
  dnl so check the version number `makeinfo' emits.
  dnl
  makeinfo_version=`$ac_cv_prog_MAKEINFO --version 2>&1 | \
                      sed -e '/[Mm]akeinfo/!d' \
                          -e 's,\ ,@,' \
                          -e 's,.*@,,' \
                          -e 's,^[a-zA-Z\ \(\)]*,,g' \
                          -e 's,).*,,'`
  makeinfo_version_prefix=`echo "$makeinfo_version" | \
                             sed -e 's,\..*,,'`
  makeinfo_version_suffix=`echo "$makeinfo_version" | \
                             sed -e 's,[a-zA-Z\-].*,,' \
                                 -e 's,\.,@,' \
                                 -e 's,.*@,,' \
                                 -e 's,\..*,,'`
  makeinfo_version_subsuffix=`echo "$makeinfo_version" | \
                                sed -e 's,[0-9\.\-]*,,'`
  if test -z "$makeinfo_version_prefix";
  then
    makeinfo_version_prefix=nil
    makeinfo_version="$makeinfo_version_prefix"
  else
    if test -z "$makeinfo_version_suffix";
    then
      makeinfo_version_suffix=nil
      makeinfo_version="$makeinfo_version_prefix.$makeinfo_version_suffix"
    else
      if test -z "$makeinfo_version_subsuffix";
      then
        makeinfo_version_subsuffix="nil"
      fi
    fi
  fi
  makeinfo_error=no
  case "$makeinfo_version_prefix" in
    nil | [0-2]) makeinfo_error=yes ;;
    3) case "$makeinfo_version_suffix" in
         nil | [0-9] | 10 | 11) makeinfo_error=yes ;;
         12) case "$makeinfo_version_subsuffix" in
               nil | [a-s] ) makeinfo_error=yes ;;
             esac
       esac
  esac
  gcal_cv_prog_MAKEINFO_VERSION="$makeinfo_version"
  changequote([, ])dnl

  AC_MSG_RESULT($gcal_cv_prog_MAKEINFO_VERSION)
  if test "$makeinfo_error" = yes; then
    gcal_cv_prog_MAKEINFO_VERSION=""
    AC_MSG_RESULT()
    AC_MSG_WARN(no automatic recreation of HTML and Info documentation files!)
    AC_MSG_WARN(the makeinfo program is out of date.)
    AC_MSG_WARN(install *GNU Texinfo-3.12t* or later in order to)
    AC_MSG_WARN(recreate the distribution *.html and *.info files.)
    AC_MSG_WARN(Makefile targets *html* and *info* will never be executed.)
    AC_MSG_RESULT()
  fi
  MAKEINFO_VERSION=$gcal_cv_prog_MAKEINFO_VERSION
  AC_SUBST(MAKEINFO_VERSION)dnl
fi