Merge branch 'ps/meson-weak-sha1-build'

Merge branch 'ps/meson-weak-sha1-build'

meson-based build now supports the unsafe-sha1 build knob.

* ps/meson-weak-sha1-build:
  meson: provide a summary of configured backends
  meson: wire up unsafe SHA1 backend
  meson: add missing dots for build options
  meson: simplify conditions for HTTPS and SHA1 dependencies
  meson: require SecurityFramework when it's used as SHA1 backend
  meson: deduplicate access to SHA1/SHA256 backend options
  meson: consistenlty spell 'CommonCrypto'