Merge bitcoin/bitcoin#21239: guix: Add codesignature attachment support for osx+win

ee883201cf134952284632e9e9ae72bf1c8c792f guix: repro: Sort find output in libtool for gcc-8 (Carl Dong)
ee0a67c32a8861eab650bf8894af06807578eba0 codesigning: Use SHA256 as digest for osslsigncode (Windows) (Carl Dong)
38eb91eb0616ed6dbe34c23e11588d130fef07f8 guix: Add codesigning functionality (Carl Dong)
bac2690e6f683fcedb883fe1d32f3c33c628a141 guix: Package codesigning tools (Carl Dong)
0a2176d47767972e4cd5ed302c1dbeedece1708b guix: Reindent existing manifest.scm (Carl Dong)
c090a3e9238ba2df07875b4708e908d8dca4ed9b Makefile.am: use APP_DIST_DIR instead of hard-coding dist (Carl Dong)

Pull request description:

  This is the last PR before we reach feature-parity with the Gitian process!

  Note: I tried using the `Makefile` inside the distsrc to make the dmg instead of manually listing out the commands, but `make` seems to want to re-make a lot of other files which broke the dmg.

  The workflow looks something like this:
  1. `env [ FOO=bar... ] ./contrib/guix/guix-build` (add additional env vars as necessary)
  2. Codesigners only:
      1.  Copy `guix-build-<short-id>/output/x86_64-apple-darwin18/bitcoin-<short-id>-osx-unsigned.tar.gz` and `guix-build-<short-id>/output/x86_64-w64-mingw32/bitcoin-<short-id>-win-unsigned.tar.gz` to signing computer
      2. Codesign with `./detached-sig-create.sh` inside the tarball
      3. Upload contents of `signature-{osx,win}.tar.gz` to https://github.com/bitcoin-core/bitcoin-detached-sigs (as a new tag)
  3. Checkout new tag for `bitcoin-core/bitcoin-detached-sigs` with the detached signatures
  4. `env [ FOO=bar... ] DETACHED_SIGS_REPO=<path/to/bitcoin-detached-sigs> ./contrib/guix/guix-codesign` (modify env vars as necessary)
  5. Make sure `guix.sigs` is cloned and updated
  6. `env GUIX_SIGS_REPO=<path/to/guix.sigs> SIGNER=0x96AB007F1A7ED999=dongcarl ./contrib/guix/guix-attest` (modify env vars as necessary)
  7. Commit your new signatures and SHA256SUMS in `guix.sigs`
  8. Optionally, after there are multiple signatures in `guix.sigs`: `env GUIX_SIGS_REPO=<path/to/guix.sigs> ./contrib/guix/guix-verify`

ACKs for top commit:
  laanwj:
    Tested ACK ee883201cf134952284632e9e9ae72bf1c8c792f
  achow101:
    ACK ee883201cf134952284632e9e9ae72bf1c8c792f

Tree-SHA512: e812a07a5f19f900600c70cb9c717769ef544a6c0c12760b5558b76b6b37df863257f3dbf38b0757e6e06e334470267e94c9f2bdbc27409d6837b1a0bfc6acbc

0 files changed, 0 insertions, 0 deletions