Merge branch 'cb/ci-make-p4-optional'

macOS CI jobs have been occasionally flaky due to tentative version
skew between perforce and the homebrew packager.  Instead of
failing the whole CI job, just let it skip the p4 tests when this
happens.

* cb/ci-make-p4-optional:
  ci: use https, not http to download binaries from perforce.com
  ci: reintroduce prevention from perforce being quarantined in macOS
  ci: avoid brew for installing perforce
  ci: make failure to find perforce more user friendly

ci/install-dependencies.sh

@@ -5,7 +5,7 @@
 
 . ${0%/*}/lib.sh
 
-P4WHENCE=http://filehost.perforce.com/perforce/r$LINUX_P4_VERSION
+P4WHENCE=https://cdist2.perforce.com/perforce/r$LINUX_P4_VERSION
 LFSWHENCE=https://github.com/github/git-lfs/releases/download/v$LINUX_GIT_LFS_VERSION
 UBUNTU_COMMON_PKGS="make libssl-dev libcurl4-openssl-dev libexpat-dev
  tcl tk gettext zlib1g-dev perl-modules liberror-perl libauthen-sasl-perl
@@ -37,13 +37,15 @@ macos-latest)
 	test -z "$BREW_INSTALL_PACKAGES" ||
 	brew install $BREW_INSTALL_PACKAGES
 	brew link --force gettext
-	brew install --cask --no-quarantine perforce || {
-		# Update the definitions and try again
-		cask_repo="$(brew --repository)"/Library/Taps/homebrew/homebrew-cask &&
-		git -C "$cask_repo" pull --no-stat --ff-only &&
-		brew install --cask --no-quarantine perforce
-	} ||
-	brew install homebrew/cask/perforce
+	mkdir -p $HOME/bin
+	(
+		cd $HOME/bin
+		wget -q "https://cdist2.perforce.com/perforce/r21.2/bin.macosx1015x86_64/helix-core-server.tgz" &&
+		tar -xf helix-core-server.tgz &&
+		sudo xattr -d com.apple.quarantine p4 p4d 2>/dev/null || true
+	)
+	PATH="$PATH:${HOME}/bin"
+	export PATH
 
 	if test -n "$CC_PACKAGE"
 	then
@@ -78,15 +80,19 @@ linux-gcc-default)
 	;;
 esac
 
-if type p4d >/dev/null && type p4 >/dev/null
+if type p4d >/dev/null 2>&1 && type p4 >/dev/null 2>&1
 then
 	echo "$(tput setaf 6)Perforce Server Version$(tput sgr0)"
 	p4d -V | grep Rev.
 	echo "$(tput setaf 6)Perforce Client Version$(tput sgr0)"
 	p4 -V | grep Rev.
+else
+	echo >&2 "WARNING: perforce wasn't installed, see above for clues why"
 fi
-if type git-lfs >/dev/null
+if type git-lfs >/dev/null 2>&1
 then
 	echo "$(tput setaf 6)Git-LFS Version$(tput sgr0)"
 	git-lfs version
+else
+	echo >&2 "WARNING: git-lfs wasn't installed, see above for clues why"
 fi