makeinfo version checking

[Alexander Kozlov]

Binutils 2.17 - 2.18 configure script requires texinfo 4.4 or 
higher to be installed. The version checking code worked for 4.4 
- 4.9 and broke with the latest texinfo 4.11:

     if ${MAKEINFO} --version \
        | egrep 'texinfo[^0-9]*([1-3][0-9]|4\.[4-9]|[5-9])' >/dev/null 2>&1; then
       :
     else
       MAKEINFO="$MISSING makeinfo"
     fi

The search pattern could be changed to

     egrep 'texinfo[^0-9]*([1-3][0-9]|4\.([4-9]|[1-9][0-9])|[5-9])'

to allow two-digit 4.xx subversions.

Regards,
Alex.