1. make -dx turns on DEBUG_SHELL which causes sh -x to be used where
possible.
2. PrintOnError() is now called when make is stopping due to an error.
This routine reports the curdir and the value of any variables listed
in MAKE_PRINT_VAR_ON_ERROR.
3. Variables set via command line, are propagated to child-makes via
MAKEFLAGS. This behaviour appears to be necessary for POSIX (according
to the GNU folk anyway).
4. Do not reset MAKEFILE when reading ".depend" as this rather eliminates the
usefulness of ${MAKEFILE}.
5. Added ${.newline} as a simple means of being able to include \n in the
result of a :@ loop expansion.
6. Set ${MAKE_VERSION} if defined. Need to come up with a useful value.
Reviewed: christos
use -j; all make's in a recursive build cooperate to limit the total
number of jobs, using a token-passing scheme.
The current token passing algorithm is similar to the one implemented
by gmake; there is a single pipe which is inherited through the entire
process hierarchy; tokens are obtained by reading a byte from the
"read end" of the pipe, and are returned by writing them to the "write
end". This exact algorithm is likely to change in the future.
Implementation details:
- Use the new trace facility to allow measurement of the
effectiveness of different token-passing schemes
- Get a token in MakeStartJobs(), return it in Make_Update()
- Eliminate Job_Full() and the jobFull global since they are
redundant with token system.
- Add an "internal" -J option (to pass the token pipe fd's down to
submakes) and a -T option for tracing.
- Change how compatMake is forced so that -j means something when
inherited by submakes.
- When waiting for a token, poll the token-passing pipe as well as
the output pipes of existing jobs.
poll() for parallel make:
- Make the poll() code behave more like the select() code: sleep for
a bit waiting for output rather than busy-wait (eww).
- Install a no-op SIGCHLD handler so that poll/select wake up early
(with -1/EINTR) when a child exits.
- Change the default sleep time from 500ms to 5 seconds since we now
wake up promptly when a child exits.
Unfortunately this revealed a deeper problem with the brk_string code.
To fix it:
- remove sharing of the buffer between brk_string invocations
- change the semantics of brk_string so that the argument array
starts with 0, and return the buffer where the strings are
stored
sjg