[9fans] Ghostscript 5.10

[Nigel Roles ngr@symbionics.co.uk]

OK. It was not the linker. It was linked correctly, but crashed so badly
there
wasn't a stackframe! The bin/file "boot image" message comes from
/sys/src/libmach/executable.c which makes a test along the following
lines in
common():

if (entrypoint & kbase)
	string = "386 Plan 9 boot image"

Since the 386 kbase is 0x80100000 executables of more than a megabyte
may pass this test.

In consultation with forsyth we think that

if (entrypoint >= kbase)

might be closer to the truth. Or even,

if ((entrypoint & kbase) == kbase)

As for gs5.10, it's fixed. An executable is available as

http://www.cotswold.demon.co.uk/gs.gz.

Note that this does not have Plan 9 bitmap output yet, but does have the
Digiboard fax support required by bin/page.

This version of gs expects the 5.10 libraries and fonts to be in
/sys/lib/gs,
so that they don't overwrite the standard 3.22 version (in
/sys/lib/ghostscript)
These can be obtained as

http://www.cotswold.demon.co.uk/lib.tar.gz

Thus Plan 9 can now display .pdf files:

gs -sDEVICE'='dfaxlow -sOUTPUTFILE'='/tmp/xxx%.3d -dNOPAUSE -dSAFER
-dQUIET whatever.pdf

page /tmp/xxx*

Or you might like to modify page.c to accept .pdf files and treat them
as if they are .ps.