Implement a workaround for an expired elpa key (#2722)

The elpa key expiration has wrought havoc among elisp repos that actually conduct proper testing, proving yet again that no good deed goes unpunished.

See also: nextcloud/docker#687 (comment)

Author: dickmao

.circleci/config.yml

@@ -5,6 +5,7 @@ commands:
   setup:
     steps:
       - checkout
+      - run: make elpa-key
       - run: make elpa
       - run: emacs --version
   test:

Makefile

@@ -21,6 +21,22 @@ all: build
 
 -include .depend
 
+.PHONY: elpa-key
+elpa-key:
+	-mkdir -p $(HOME)/.emacs.d/elpa/gnupg
+	chmod 700 $(HOME)/.emacs.d/elpa/gnupg
+	( for i in 1 2 3 ; do \
+	    gpg --keyserver hkp://ipv4.pool.sks-keyservers.net --homedir $(HOME)/.emacs.d/elpa/gnupg --recv-keys 066DAFCB81E42C40 ; \
+	    if gpg -q --homedir $(HOME)/.emacs.d/elpa/gnupg -k | grep 81E42C40 ; then \
+	      exit 0 ; \
+	    fi ; \
+	    sleep 5 ; \
+	  done ; \
+	  exit 1 ; \
+	)
+	-mkdir -p $(shell $(CASK) package-directory)
+	cp -pr $(HOME)/.emacs.d/elpa/gnupg $(shell $(CASK) package-directory)
+
 elpa-$(EMACS):
 	$(CASK) install
 	$(CASK) update