maint: Use consistent coding style for build helper shell scripts * mk-octave-config-h.sh: Keep if-then on a single line. * move-if-change: Insert a space in interpreter directive for consistency. * build-env-features.sh, config-images.sh, config-module.sh, config-ops.sh, find-defun-files.sh, find-files-with-tests.sh, mk-errno-list, libinterp/mk-pkg-add, scripts/mk-pkg-add, mkbuiltins, mkdefs, mkdocs, mkf77def.in, mkops: Initialize environment variable defaults consistently. Use shift only when the argument list is not empty. Remove unnecessary quotes and semicolons on variable assignments. Insert/remove blank lines for consistency.

#! /bin/sh

set -e

GREP=${GREP:-grep}
SED=${SED:-sed}

srcdir="$1"
if [ "$1" ]; then
  shift
fi

for arg
do
  if [ -f "$arg" ]; then
    file="$arg"
  else
    file="$srcdir/$arg"
  fi
  if [ -f "$file" ]; then
    if [ "`$GREP -l '^%!' $file`" ]; then
      echo "$file" | $SED "s,\\$srcdir/,,"
    fi
  fi
done