The layer order was not correct when a parent image was used: parent
image layers were above the new created layer.
This commits simplifies the code related to layer ordering. In
particular, layers in `layer-list` are ordered from bottom-most to
top-most. This is also the order of layers in the `rootfs.diff_ids`
attribute of the image configuration.
Especially as a new user it is a much better experience to receive a
proper help response to `-h`. Currently passing `-h` will cause some
runtime error with the `git remote` error help being shown. Not very
helpful.
It doesn't hurt to be a bit more user friendly in this case.
We want to make sure this value is explicitly set. Infering it for
every arch leads to annoying failures like:
https://hydra.nixos.org/build/92583832/
Perhaps we can enable it in the future with some smarter handling of
cc-wrapper.sh.
Creating the timestamp in the patched script's directory has a few
drawbacks:
* if "foo.timestamp" already exists, it will be overwritten
* it requires the directory to be writable
Adds pkgsCross.wasm32 and pkgsCross.wasm64. Use it to build Nixpkgs
with a WebAssembly toolchain.
stdenv/cross: use static overlay on isWasm
isWasm doesn’t make sense dynamically linked.
It is useful to make these dynamic and not bake them into gcc. This
means we don’t have to rebuild gcc to change these values. Instead, we
will pass cflags to gcc based on platform values. This was already
done hackily for android gcc (which is multi-target), but not for our
own gccs which are single target.
To accomplish this, we need to add a few things:
- add ‘arch’ to cpu
- add NIX_CFLAGS_COMPILE_BEFORE flag (goes before args)
- set -march everywhere
- set mcpu, mfpu, mmode, and mtune based on targetPlatform.gcc flags
cc-wrapper: only set -march when it is in the cpu type
Some architectures don’t have a good mapping of -march. For instance
POWER architecture doesn’t support the -march flag at all!
https://gcc.gnu.org/onlinedocs/gcc/RS_002f6000-and-PowerPC-Options.html#RS_002f6000-and-PowerPC-Options
gobject-introspection uses glib’s g_module_open function, which in turn relies
on dlopen. I also implemented openat, since I initially thought this function
was used but turns out dlopen uses the openat signal directly. We might as
well keep it, even thought I do not need it at the moment.
