[9fans] problems with marshal

[rog@vitanuova.com]

i came across a few problems with upas/marshal; i'm afraid i haven't
got time to fix all of them right now.

most minor problem is that in scanning for 8 bit characters, a
"Content-transfer-encoding: 8bit" header can be output several times.

that's fixed easily with:
diff /n/dump/2000/1121/sys/src/cmd/upas/ned/marshal.c marshal.c
370c370
< 		for(;;){
---
> 		while (docontenttype){
385c385
< 				if(*p++ & 0x80){
---
> 				if(*p++ & 0x80 && docontenttype){

(which also saves some buffer space on files containing lots of utf)

the other problem is that text attachments containing 8 bit utf don't
propagate the "Content-transfer-encoding: 8bit" into the main header.
fixing this would require reading all the attachments before spitting
out the principal header, which is not currently done.

the alternative (which would likely be preferable, as it would make
the resulting email smtp compatible) would be to encode any 8-bit
plain text attachments in quoted-printable.  then i might be able to
see the utf chars sent to 9fans!

one last thing:
diff /n/dump/2000/1121/sys/src/cmd/file.c file.c
345c345
< 	if (nbuf < 100)
---
> 	if (nbuf < 100 && !mime)

which stops "file -m" printing two type lines for short files.

  cheers,
    rog.