use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

This code could be possible reused on low-end targets with limited RAM.

code to generate lookup table:
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/* CRC lookup table and initial state. */
uint32_t crc32_table[256];

/* Generate CRC32 lookup table. */
void GenerateCRC32Table(void)
{
unsigned int i, j;
/* Use CRC-32-IEEE 802.3 polynomial 0x04C11DB7 (bit reflected). */
uint32_t poly = 0xEDB88320;

for (i = 0; i <= 0xFF; i++)
{
uint32_t c = i;
for (j = 0 ; j < 8 ; j++)
c = (c & 1) ? (c >> 1 ) ^ poly : (c >> 1);
crc32_table[i] = c;
}
}

void main(void)
{
GenerateCRC32Table();
int j=0;
for(int i=0; i<256; i++) {
printf("0x%08X, ", crc32_table[i]);
if (++j >= 8) {
j = 0;
printf("\n");
}
}
}
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#!/bin/bash

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INKSCAPE=inkscape

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for i in `cat icons.svg |grep -o -e '%%[^%]*%%'|sed 's/%//g'` 

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do

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 if [ $i.png -nt icons.svg ]; then

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 	echo "Skip $i"

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 else

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	rm  -f $i.png

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	echo "$INKSCAPE" icons.svg -z -e $i.png -i $i

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	"$INKSCAPE" icons.svg -z -e $i.png -i $i

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 fi

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done

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