@unless __exmr_m1__
@define __expr_m1__ 1
@comment expr.m1 by Ben Collver, Usage:
@comment
@comment     @include expr.m1
@comment     @expr@ varname @(@ expression @)@
@comment
@comment Shell AWK sub-process to evaluate arithmetic expression.
@comment Assign result to varname.  If ARGV0 is defined use that.
@comment Otherwise, default to "awk".
@unless ARGV0
@define awk awk
@fi
@unless awk
@define awk @ARGV0@
@fi
@define expr @shell
@define ( @awk@ 'BEGIN {print (
@define ) )}'
@fi