[Boost-build] Patch jam.h for vacpp piecemeal archive action

From: K. Noel Belcourt (kbelco_at_[hidden])
Date: 2007-07-03 15:30:55

Hi,

On AIX, the maximum shell argument length can be found with, lsattr - 
D -l sys0, which on our systems yields

ncargs          6       ARG/ENV list size in 4K byte  
blocks               True

which is 24576 bytes.  There is no AIX specific value for MAXLINE in  
jam.h, so it uses the default value of 102400 bytes, which is far too  
big for the default AIX configuration.  I've tested the piecemeal  
archive action with a MAXLINE = 23552 (23k), and this seems to work  
fine.  Note that I can't set it to exactly 24k since it breaks  
piecemeal.

The attached patch sets the MAXLINE length for AIX to be 23552  
bytes.  If there's no objection, I'd like to commit this to cvs head.

-- Noel Belcourt