sym_openmp error in configure script

[casper-murtonen]

The test for gcc version in the configure script, when setting sym_openmp, does not work for gcc version 10:

     g++*)
        sym_openmp=true
        fopenmp_version=4.2
        gcc_required_version=`echo ${fopenmp_version} | sed -e 's/\./0/g'`
        get_gcc_version=`$CXX -dumpversion`
        gcc_version=`echo ${get_gcc_version} | sed -e 's/\./0/g'`
        major_gcc_version=`echo ${gcc_version:0:3}`
        #AC_MSG_RESULT([$get_gcc_version])
        if test ${major_gcc_version} -lt ${gcc_required_version}; then
           echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
           sym_openmp=false
        else
           echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
           sym_openmp=true
        fi
        ;;

1. On my system gcc -dumpversion returns simply "10" so there is no '.' to replace with a '0', so major_gcc_version = "10" not "1000" as required.
2. In any case if it did return "10.0" which might have been expected, truncation to 3 characters would leave only "100" not "1000".

The simple user workaround is to explicitly build with --enable-openmp