fa2056af1c travis: Properly cache and error on timeout (MarcoFalke)
fa36a333ee travis: Switch to ubuntu keyserver to avoid timeouts (MarcoFalke)
Pull request description:
The other keyserver is consistently timing out on travis: https://travis-ci.org/bitcoin/bitcoin/jobs/512689710#L405
Attempt to fix it by using a different server.
Also:
* fixes#15372
* fixes#15738
ACKs for commit fa2056:
ryanofsky:
utACK fa2056af1c71aded3a821a07ec4de71c4be0bca3. All good changes (changing keyserver, getting rid of keyserver while loop, clarifying travis error, moving travis documentation to code comment).
Tree-SHA512: ac8436616ecfee0ed579114e19f03c53ceb688fbcd95a60cffe8f15b4e569772a6ba673f353bbd789e79fe27fc5626c77fab4086768844dd51e0c6c108b52fb2
fa677d1801fb9153a95a1fc9855fd5f21fc440c0 ci: Remove redundant check for TRAVIS_OS_NAME (MarcoFalke)
fadccb263baf6b8694f750623add42f966e423a3 doc: Document that GNU tools are required for linters (MarcoFalke)
4444704ca9f66cdc24ab2d444941354db1dfed06 ci: Cleanup macOS runs (MarcoFalke)
Pull request description:
* Remove a commented out cleanup task in `before_cache`
* Remove the linter run on macOS, and document that GNU tools are required to run the linters
ACKs for top commit:
Sjors:
Code review ACK fa677d1801fb9153a95a1fc9855fd5f21fc440c0
laanwj:
ACK fa677d1801fb9153a95a1fc9855fd5f21fc440c0
ryanofsky:
Code review ACK fa677d1801fb9153a95a1fc9855fd5f21fc440c0 for new third commit replacing TRAVIS_OS_NAME check with NO_DEPENDS setting
Tree-SHA512: 9122a63bbe7887d9e379123152ea4ba44324cb18033b9e6b45bfdb1af665c10ea598564b9fcd57330d208a08e4696e41b4d6175f05f0843a3a76530da114f8c6
