[barcode] Solaris9, build fails -> patch offered.

[Alessandro Rubini]

> code128.c:219: warning: subscript has type `char'
> code128.c:219: warning: subscript has type `char'
> code128.c: In function `Barcode_128_encode':
> code128.c:467: warning: subscript has type `char'

Ok, I converted all text strings to  "unsigned char". Thanks.

> awk -f doc/manpager doc/doc.barcode
> awk: syntax error near line 23

Actually, I had two students studying compatibility issues
across the various awk flavours, but I didn't manage to integrate
their results into a portable doc/manpager.

I applied your patch, which looks a good step forward to me (independently of
making the tool portable).

However, currently on my system mawk is selected, and it produces
an incorrect man page (original-awk and gawk produce correct ones,
mawk and nawk do not; gawk spits a warning, the other ones do not).
This is what I get in configure:
	for ac_prog in mawk gawk nawk awk; [...]
while the documentation states:
	Check for `gawk', `mawk', `nawk', and `awk', in that order,

This is the type of incorrectness: no blanks in indented paragraphs.

       -i filename
              Identifyafilewherestringstobeencodedarereadfrom.If
              missing(andif-bisnotused)itdefaultstostandard
              input.Eachdatalineoftheinputfilewillbeusedtocreate
              onebarcodeoutput.

Thus, I must recover my students' work now :)

Thanks
/alessandro