Don't bind-mount these to themselves,
mount them into the chroot directory.
Fixes pty issues when using sandbox on CentOS 7.4.
(build of perlPackages.IOTty fails before this change)
Fixes
error: getting status of '/nix/store/j8p0vv89k1pf0cn7kmfsdcs7bshwga1i-firefox-52.7.2esr/share/icons/hicolor/48x48/apps/firefox.png': No such file or directory
https://github.com/NixOS/nix/issues/1934
Also improve error message on directory/non-directory collisions.
For instance, this reduced the memory consumption of
$ nix copy --from ssh://localhost --to ~/my-nix /nix/store/1n7x0yv8vq6zi90hfmian84vdhd04bgp-blender-2.79a
from 632 MiB to 16 MiB.
E.g.
cannot build on 'ssh://mac1': cannot connect to 'mac1': bash: nix-store: command not found
cannot build on 'ssh://mac2': cannot connect to 'mac2': Host key verification failed.
cannot build on 'ssh://mac3': cannot connect to 'mac3': Received disconnect from 213... port 6001:2: Too many authentication failures
Authentication failed.
copyStorePath() now pipes the output of srcStore->narFromPath()
directly into dstStore->addToStore(). The sink used by the former is
converted into a source usable by the latter using
boost::coroutine2. This is based on [1].
This reduces the maximum resident size of
$ nix build --store ~/my-nix/ /nix/store/b0zlxla7dmy1iwc3g459rjznx59797xy-binutils-2.28.1 --substituters file:///tmp/binary-cache-xz/ --no-require-sigs
from 418592 KiB to 53416 KiB. (The previous commit also reduced the
runtime from ~4.2s to ~3.4s, not sure why.) A further improvement will
be to download files into a Sink.
[1] https://github.com/NixOS/nix/compare/master...Mathnerd314:dump-fix-coroutine#diff-dcbcac55a634031f9cc73707da6e4b18
Issue #1969.
This can be iterated on and currently leaves out settings we know we
want to forward, but it fixes#1713 and fixes#1935 and isn't
fundamentally broken like the status quo. Future changes are suggested
in a comment.
This allows building armv[67]l-linux derivations on compatible aarch64
machines. Failure to add the architecture may result from missing
hardware support, in which case we can't run 32-bit binaries and don't
need to restrict them with seccomp anyway,
This allows specifying additional systems that a machine is able to
build for. This may apply on some armv7-capable aarch64 processors, or
on systems using qemu-user with binfmt-misc to support transparent
execution of foreign-arch programs.
This removes the previous hard-coded assumptions about which systems are
ABI-compatible with which other systems, and instead relies on the user
to specify any additional platforms that they have ensured compatibility
for and wish to build for locally.
NixOS should probably add i686-linux on x86_64-linux systems for this
setting by default.
The overhead of sandbox builds is a problem on NixOS (since building a
NixOS configuration involves a lot of small derivations) but not for
typical non-NixOS use cases. So outside of NixOS we can enable it.
Issue #179.
Previously, this would fail at startup for non-NixOS installs:
nix-env --help
The fix for this is to just use "nixManDir" as the value for MANPATH
when spawning "man".
To test this, I’m using the following:
$ nix-build release.nix -A build
$ MANPATH= ./result/bin/nix-env --help
Fixes#1627
This was caused by derivations with 'allowSubstitutes = false'. Such
derivations will be built locally. However, if there is another
SubstitionGoal that has the output of the first derivation in its
closure, then the path will be simultaneously built and substituted.
There was a check to catch this situation (via pathIsLockedByMe()),
but it no longer worked reliably because substitutions are now done in
another thread. (Thus the comment 'It can't happen between here and
the lockPaths() call below because we're not allowing multi-threading'
was no longer valid.)
The fix is to handle the path already being locked in both
SubstitutionGoal and DerivationGoal.
All ANSI sequences except color setting are now filtered out. In
particular, terminal resets (such as from NixOS VM tests) are filtered
out.
Also, fix the completely broken tab character handling.
builtins.path allows specifying the name of a path (which makes paths
with store-illegal names now addable), allows adding paths with flat
instead of recursive hashes, allows specifying a filter (so is a
generalization of filterSource), and allows specifying an expected
hash (enabling safe path adding in pure mode).
This is needed by nixos-install, which uses the Nix store on the
installation CD as a substituter. We don't want to disable signature
checking entirely because substitutes from cache.nixos.org should
still be checked. So now we can pas "local?trusted=1" to mark only the
Nix store in /nix as not requiring signatures.
Fixes#1819.
Instead, if a fixed-output derivation produces has an incorrect output
hash, we now unconditionally move the outputs to the path
corresponding with the actual hash and register it as valid. Thus,
after correcting the hash in the Nix expression (e.g. in a fetchurl
call), the fixed-output derivation doesn't have to be built again.
It would still be good to have a command for reporting the actual hash
of a fixed-output derivation (instead of throwing an error), but
"nix-build --hash" didn't do that.
Following discussion with Shea and Graham. It's a big enough change
from the last release. Also, from a semver perspective, 2.0 makes more
sense because we did remove some interfaces (like nix-pull/nix-push).
Some servers, such as Artifactory, allow uploading with PUT and BASIC
auth. This allows nix copy to work to upload binaries to those
servers.
Worked on together with @adelbertc
In this mode, the following restrictions apply:
* The builtins currentTime, currentSystem and storePath throw an
error.
* $NIX_PATH and -I are ignored.
* fetchGit and fetchMercurial require a revision hash.
* fetchurl and fetchTarball require a sha256 attribute.
* No file system access is allowed outside of the paths returned by
fetch{Git,Mercurial,url,Tarball}. Thus 'nix build -f ./foo.nix' is
not allowed.
Thus, the evaluation result is completely reproducible from the
command line arguments. E.g.
nix build --pure-eval '(
let
nix = fetchGit { url = https://github.com/NixOS/nixpkgs.git; rev = "9c927de4b179a6dd210dd88d34bda8af4b575680"; };
nixpkgs = fetchGit { url = https://github.com/NixOS/nixpkgs.git; ref = "release-17.09"; rev = "66b4de79e3841530e6d9c6baf98702aa1f7124e4"; };
in (import (nix + "/release.nix") { inherit nix nixpkgs; }).build.x86_64-linux
)'
The goal is to enable completely reproducible and traceable
evaluation. For example, a NixOS configuration could be fully
described by a single Git commit hash. 'nixos-rebuild' would do
something like
nix build --pure-eval '(
(import (fetchGit { url = file:///my-nixos-config; rev = "..."; })).system
')
where the Git repository /my-nixos-config would use further fetchGit
calls or Git externals to fetch Nixpkgs and whatever other
dependencies it has. Either way, the commit hash would uniquely
identify the NixOS configuration and allow it to reproduced.
E.g.
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nars \
/nix/store/b0w2hafndl09h64fhb86kw6bmhbmnpm1-blender-2.79/share/icons/hicolor/scalable/apps/blender.svg > /dev/null
real 0m4.139s
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nars \
/nix/store/b0w2hafndl09h64fhb86kw6bmhbmnpm1-blender-2.79/share/icons/hicolor/scalable/apps/blender.svg > /dev/null
real 0m0.024s
(Before, the second call took ~0.220s.)
This will use a NAR listing in
/tmp/nars/b0w2hafndl09h64fhb86kw6bmhbmnpm1.ls containing all metadata,
including the offsets of regular files inside the NAR. Thus, we don't
need to read the entire NAR. (We do read the entire listing, but
that's generally pretty small. We could use a SQLite DB by borrowing
some more code from nixos-channel-scripts/file-cache.hh.)
This is primarily useful when Hydra is serving files from an S3 binary
cache, in particular when you have giant NARs. E.g. we had some 12 GiB
NARs, so accessing individuals files was pretty slow.
The name had become a misnomer since it's not only for substitution
from binary caches, but when adding/copying any
(non-content-addressed) path to a store.
This allows specifying the AWS configuration profile to use. E.g.
nix copy --from s3://my-cache?profile=aws-dev-account /nix/store/cf3isrlqavvd5w7rpky1fa8j9lcnlggm-...
As far as we're concerned, not being able to access a file just means
the file is missing. Plus, AWS explicitly goes out of its way to
return a 403 if the file is missing and the requester doesn't have
permission to list the bucket.
Also getting rid of an old hack that Eelco said was only relevant
to an older AWS SDK.
This will allow bind and connect to 127.0.0.1, which can reduce purity/
security (if you're running a vulnerable service on localhost) but is
also needed for a ton of test suites, so I'm leaving it turned off by
default but allowing certain derivations to turn it on as needed.
It also allows DNS resolution of arbitrary hostnames but I haven't found
a way to avoid that. In principle I'd just want to allow resolving
localhost but that doesn't seem to be possible.
I don't think this belongs under `build-use-sandbox = relaxed` because we
want it on Hydra and I don't think it's the end of the world.
The computation of urlHash didn't take the name into account, so
subsequent fetchurl calls with the same URL but a different name would
resolve to the same cached store path.
You can now include files via the "builders" option, using the syntax
"@<filename>". Having only one option makes it easier to override
builders completely.
For backward compatibility, the default is "@/etc/nix/machines", or
"@<filename>" for each file name in NIX_REMOTE_SYSTEMS.
This makes it slightly more manageable to see at a glance what in a
build's sandbox profile is unique to the build and what is standard. Also
a first step to factoring more of our Darwin logic into scheme functions
that will allow us a bit more flexibility. And of course less of that
nasty codegen in C++! 😀
This speeds up commands like "nix cat-store". For example:
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nar-cache /nix/store/i60yncmq6w9dyv37zd2k454g0fkl3arl-systemd-234/etc/udev/udev.conf
real 0m4.336s
$ time nix cat-store --store https://cache.nixos.org?local-nar-cache=/tmp/nar-cache /nix/store/i60yncmq6w9dyv37zd2k454g0fkl3arl-systemd-234/etc/udev/udev.conf
real 0m0.045s
The primary motivation is to allow hydra-server to serve files from S3
binary caches. Previously Hydra had a hack to do "nix-store -r
<path>", but that fetches the entire closure so is prohibitively
expensive.
There is no garbage collection of the NAR cache yet. Also, the entire
NAR is read when accessing a single member file. We could generate the
NAR listing to provide random access.
Note: the NAR cache is indexed by the store path hash, not the content
hash, so NAR caches should not be shared between binary caches, unless
you're sure that all your builds are binary-reproducible.
Probably as a result of a bad merge in
4b8f1b0ec0, we had both a
BinaryCacheStoreAccessor and a
RemoteFSAccessor. BinaryCacheStore::getFSAccessor() returned the
latter, but BinaryCacheStore::addToStore() checked for the
former. This probably caused hydra-queue-runner to download paths that
it just uploaded.
I needed this to test ACL/xattr removal in
canonicalisePathMetaData(). Might also be useful if you need to build
old Nixpkgs that doesn't have the required patches to remove
setuid/setgid creation.
It was getting too much like whac-a-mole listing all the retriable error
conditions, so we now retry by default and list the cases where retrying
is almost certainly hopeless.
This is a hack to make hydra-queue-runner free its temproots
periodically, thereby ensuring that garbage collection of the
corresponding paths is not blocked until the queue runner is
restarted.
It would be better if temproots could be released earlier than at
process exit. I started working on a RAII object returned by functions
like addToStore() that releases temproots. However, this would be a
pretty massive change so I gave up on it for now.
For example,
$ nix-store -q --roots /nix/store/7phd2sav7068nivgvmj2vpm3v47fd27l-patchelf-0.8pre845_0315148
{temp:1}
denotes that the path is only being kept alive by a temporary root
(i.e. /nix/var/nix/temproots/). Similarly,
$ nix-store --gc --print-roots
...
{memory:9} -> /nix/store/094gpjn9f15ip17wzxhma4r51nvsj17p-curl-7.53.1
shows that curl is being used by some process.
Since we may use a dedicated file descriptor in the future, this
allows us to change it. So builders can do
if [[ -n $NIX_LOG_FD ]]; then
echo "@nix { message... }" >&$NIX_LOG_FD
fi
Nix can now automatically run the garbage collector during builds or
while adding paths to the store. The option "min-free = <bytes>"
specifies that Nix should run the garbage collector whenever free
space in the Nix store drops below <bytes>. It will then delete
garbage until "max-free" bytes are available.
Garbage collection during builds is asynchronous; running builds are
not paused and new builds are not blocked. However, there also is a
synchronous GC run prior to the first build/substitution.
Currently, no old GC roots are deleted (as in "nix-collect-garbage
-d").
Since file locks are per-process rather than per-file-descriptor, the
garbage collector would always acquire a lock on its own temproots
file and conclude that it's stale.
Without this, substitute info is fetched sequentially, which is
superslow. In the old UI (e.g. nix-build), we call printMissing(),
which calls queryMissing(), thereby preheating the binary cache
cache. But the new UI doesn't do that.
In particular, drop the "build-" and "gc-" prefixes which are
pointless. So now you can say
nix build --no-sandbox
instead of
nix build --no-build-use-sandbox
In particular, don't use base-64, which we don't support. (We do have
base-32 redirects for hysterical reasons.)
Also, add a test for the hashed mirror feature.
This allows builds to call setuid binaries. This was previously
possible until we started using seccomp. Turns out that seccomp by
default disallows processes from acquiring new privileges. Generally,
any use of setuid binaries (except those created by the builder
itself) is by definition impure, but some people were relying on this
ability for certain tests.
Example:
$ nix build '(with import <nixpkgs> {}; runCommand "foo" {} "/run/wrappers/bin/ping -c 1 8.8.8.8; exit 1")' --no-allow-new-privileges
builder for ‘/nix/store/j0nd8kv85hd6r4kxgnwzvr0k65ykf6fv-foo.drv’ failed with exit code 1; last 2 log lines:
cannot raise the capability into the Ambient set
: Operation not permitted
$ nix build '(with import <nixpkgs> {}; runCommand "foo" {} "/run/wrappers/bin/ping -c 1 8.8.8.8; exit 1")' --allow-new-privileges
builder for ‘/nix/store/j0nd8kv85hd6r4kxgnwzvr0k65ykf6fv-foo.drv’ failed with exit code 1; last 6 log lines:
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=46 time=15.2 ms
Fixes#1429.
Functions like copyClosure() had 3 bool arguments, which creates a
severe risk of mixing up arguments.
Also, implement copyClosure() using copyPaths().
Cygwin sqlite3 is patched to call SetDllDirectory("/usr/bin") on init, which
affects the current process and is inherited by child processes. It causes
DLLs to be loaded from /usr/bin/ before $PATH, which breaks all sorts of
things. A typical failures would be header/lib version mismatches (e.g.
openssl when running checkPhase on openssh). We'll just set it back to the
default value.
Note that this is a problem with the cygwin version of sqlite3 (currently
3.18.0). nixpkgs doesn't have the problematic patch.
Recently aws-sdk-cpp quietly switched to using S3 virtual host URIs
(https://github.com/aws/aws-sdk-cpp/commit/69d9c53882), i.e. it sends
requests to http://<bucket>.<region>.s3.amazonaws.com rather than
http://<region>.s3.amazonaws.com/<bucket>. However this interacts
badly with curl connection reuse. For example, if we do the following:
1) Check whether a bucket exists using GetBucketLocation.
2) If it doesn't, create it using CreateBucket.
3) Do operations on the bucket.
then 3) will fail for a minute or so with a NoSuchBucket exception,
presumably because the server being hit is a fallback for cases when
buckets don't exist.
Disabling the use of virtual hosts ensures that 3) succeeds
immediately. (I don't know what S3's consistency guarantees are for
bucket creation, but in practice buckets appear to be available
immediately.)
Newer versions of aws-sdk-cpp call CalculateDelayBeforeNextRetry()
even for non-retriable errors (like NoSuchKey) whih causes log spam in
hydra-queue-runner.
Sandboxes cannot be nested, so if Nix's build runs inside a sandbox,
it cannot use a sandbox itself. I don't see a clean way to detect
whether we're in a sandbox, so use a test-specific hack.
https://github.com/NixOS/nix/issues/1413
In particular, UF_IMMUTABLE (uchg) needs to be cleared to allow the
path to be garbage-collected or optimised.
See https://github.com/NixOS/nixpkgs/issues/25819.
+ the file from being garbage-collected.
Thus, instead of ‘--option <name> <value>’, you can write ‘--<name>
<value>’. So
--option http-connections 100
becomes
--http-connections 100
Apart from brevity, the difference is that it's not an error to set a
non-existent option via --option, but unrecognized arguments are
fatal.
Boolean options have special treatment: they're mapped to the
argument-less flags ‘--<name>’ and ‘--no-<name>’. E.g.
--option auto-optimise-store false
becomes
--no-auto-optimise-store
Even with "build-use-sandbox = false", we now use sandboxing with a
permissive profile that allows everything except the creation of
setuid/setgid binaries.
Also, add rules to allow fixed-output derivations to access the
network.
These rules are sufficient to build stdenvDarwin without any
__sandboxProfile magic.
The filename used was not unique and owned by the build user, so
builds could fail with
error: while setting up the build environment: cannot unlink ‘/nix/store/99i210ihnsjacajaw8r33fmgjvzpg6nr-bison-3.0.4.drv.sb’: Permission denied
Fixes
src/libstore/build.cc:2321:45: error: non-constant-expression cannot be narrowed from type 'int' to 'scmp_datum_t' (aka 'unsigned long') in initializer list [-Wc++11-narrowing]
EAs/ACLs are not part of the NAR canonicalisation. Worse, setting an
ACL allows a builder to create writable files in the Nix store. So get
rid of them.
Closes#185.
This prevents builders from setting the S_ISUID or S_ISGID bits,
preventing users from using a nixbld* user to create a setuid/setgid
binary to interfere with subsequent builds under the same nixbld* uid.
This is based on aszlig's seccomp code
(47f587700d).
Reported by Linus Heckemann.
Fixes
client# error: size mismatch importing path ‘/nix/store/ywf5fihjlxwijm6ygh6s0a353b5yvq4d-libidn2-0.16’; expected 0, got 120264
This is mostly an artifact of the NixOS VM test environment, where the
Nix database doesn't contain hashes/sizes.
http://hydra.nixos.org/build/53537471
And add a 116 KiB ash shell from busybox to the release build. This
helps to make sandbox builds work out of the box on non-NixOS systems
and with diverted stores.
This is useful when we're using a diverted store (e.g. "--store
local?root=/tmp/nix") in conjunction with a statically-linked sh from
the host store (e.g. "sandbox-paths =/bin/sh=/nix/store/.../bin/busybox").
Previously, if a directory `foo` existed and a file `foo-` (where `-` is any character that is sorted before `/`), then `readDirectory` would return an empty list.
To fix this, we now use a tree where we can just access the children of the node, and do not need to rely on sorting behavior to list the contents of a directory.
It now means "paths that were built locally". It no longer includes
paths that were added locally. For those we don't need info.ultimate,
since we have the content-addressability assertion (info.ca).
There is a security issue when a build accidentally stores its $TMPDIR
in some critical place, such as an RPATH. If
TMPDIR=/tmp/nix-build-..., then any user on the system can recreate
that directory and inject libraries into the RPATH of programs
executed by other users. Since /build probably doesn't exist (or isn't
world-writable), this mitigates the issue.
Opening an SSHStore or LegacySSHStore does not actually establish a
connection, so the try/catch block here did nothing. Added a
Store::connect() method to test whether a connection can be
established.
This is useful for one-off situations where you want to specify a
builder on the command line instead of having to mess with
nix.machines. E.g.
$ nix-build -A hello --argstr system x86_64-darwin \
--option builders 'root@macstadium1 x86_64-darwin'
will perform the specified build on "macstadium1".
It also removes the need for a separate nix.machines file since you
can specify builders in nix.conf directly. (In fact nix.machines is
yet another hack that predates the general nix.conf configuration
file, IIRC.)
Note: this option is supported by the daemon for trusted users. The
fact that this allows trusted users to specify paths to SSH keys to
which they don't normally have access is maybe a bit too much trust...
For backwards compatibility, if the URI is just a hostname, ssh://
(i.e. LegacySSHStore) is prepended automatically.
Also, all fields except the URI are now optional. For example, this is
a valid nix.machines file:
local?root=/tmp/nix
This is useful for testing the remote build machinery since you don't
have to mess around with ssh.
This is to simplify remote build configuration. These environment
variables predate nix.conf.
The build hook now has a sensible default (namely build-remote).
The current load is kept in the Nix state directory now.
Since build-remote uses buildDerivation() now, we don't need to copy
the .drv file anymore. This greatly reduces the set of input paths
copied to the remote side (e.g. from 392 to 51 store paths for GNU
hello on x86_64-darwin).
This default implementation of buildPaths() does nothing if all
requested paths are already valid, and throws an "unsupported
operation" error otherwise. This fixes a regression introduced by
c30330df6f in binary cache and legacy
SSH stores.
The typical use is to inherit Config and add Setting<T> members:
class MyClass : private Config
{
Setting<int> foo{this, 123, "foo", "the number of foos to use"};
Setting<std::string> bar{this, "blabla", "bar", "the name of the bar"};
MyClass() : Config(readConfigFile("/etc/my-app.conf"))
{
std::cout << foo << "\n"; // will print 123 unless overriden
}
};
Currently, this is used by Store and its subclasses for store
parameters. You now get a warning if you specify a non-existant store
parameter in a store URI.
This provides a significant speedup, e.g. 64 s -> 12 s for
nix-build --dry-run -I nixpkgs=channel:nixos-16.03 '<nixpkgs/nixos/tests/misc.nix>' -A test
on a cold local and CloudFront cache.
The alternative is to use lots of concurrent daemon connections but
that seems wasteful.
This is useless because the client also caches path info, and can
cause problems for long-running clients like hydra-queue-runner
(i.e. it may return cached info about paths that have been
garbage-collected).
This fixes "No such file or directory" when opening /dev/ptmx
(e.g. http://hydra.nixos.org/build/51094249).
The reason appears to be some changes to /dev/ptmx / /dev/pts handling
between Linux 4.4 and 4.9. See
https://patchwork.kernel.org/patch/7832531/.
The fix is to go back to mounting a proper /dev/pts instance inside
the sandbox. Happily, this now works inside user namespaces, even for
unprivileged users. So
NIX_REMOTE=local?root=/tmp/nix nix-build \
'<nixpkgs/nixos/tests/misc.nix>' -A test
works for non-root users.
The downside is that the fix breaks sandbox builds on older kernels
(probably pre-4.6), since mounting a devpts fails inside user
namespaces for some reason I've never been able to figure out. Builds
on those systems will fail with
error: while setting up the build environment: mounting /dev/pts: Invalid argument
Ah well.
Execute a given program with the (optional) given arguments as the
user running the evaluation, parsing stdout as an expression to be
evaluated.
There are many use cases for nix that would benefit from being able to
run arbitrary code during evaluation, including but not limited to:
* Automatic git fetching to get a sha256 from a git revision
* git rev-parse HEAD
* Automatic extraction of information from build specifications from
other tools, particularly language-specific package managers like
cabal or npm
* Secrets decryption (e.g. with nixops)
* Private repository fetching
Ideally, we would add this functionality in a more principled way to
nix, but in the mean time 'builtins.exec' can be used to get these
tasks done.
The primop is only available when the
'allow-unsafe-native-code-during-evaluation' nix option is true. That
flag also enables the 'importNative' primop, which is strictly more
powerful but less convenient (since it requires compiling a plugin
against the running version of nix).
So if "text-compression=br", the .ls file in S3 will get a
Content-Encoding of "br". Brotli appears to compress better than xz
for this kind of file and is natively supported by browsers.
You can now set the store parameter "text-compression=br" to compress
textual files in the binary cache (i.e. narinfo and logs) using
Brotli. This sets the Content-Encoding header; the extension of
compressed files is unchanged.
You can separately specify the compression of log files using
"log-compression=br". This is useful when you don't want to compress
narinfo files for backward compatibility.
Build logs on cache.nixos.org are compressed using Brotli (since this
allows them to be decompressed automatically by Chrome and Firefox),
so it's handy if "nix log" can decompress them.
This allows various Store implementations to provide different ways to
get build logs. For example, BinaryCacheStore can get the build logs
from the binary cache.
Also, remove the log-servers option since we can use substituters for
this.
* Unify SSH code in SSHStore and LegacySSHStore.
* Fix a race starting the SSH master. We now wait synchronously for
the SSH master to finish starting. This prevents the SSH clients
from starting their own connections.
* Don't use a master if max-connections == 1.
* Add a "max-connections" store parameter.
* Add a "compress" store parameter.
"build-max-jobs" and the "-j" option can now be set to "auto" to use
the number of CPUs in the system. (Unlike build-cores, it doesn't use
0 to imply auto-configuration, because a) magic values are a bad idea
in general; b) 0 is a legitimate value used to disable local
building.)
Fixes#1198.
Linus Heckemann
Jörg Thalheim