DiffieHellman: gracefully handle platforms that fail the sha256 self test, currently only known to be PowerPC. Added support for PHP's built-in hash functions (they were added in 5.1.2) and use them in lieu of the built-in sha256 implementation when available.

#!/bin/bash
for f in *.svg; do
    echo Converting $f
    fname=`echo $f | cut -d '.' -f 1`
    rm -f $fname.png
    inkscape -z -f $f -w 22 -h 22 -e ./$fname.png
done