ci: Implement gen_install.sh

ci/release/gen_install.sh

@@ -1,2 +1,33 @@
 #!/bin/sh
 set -eu
+cd -- "$(dirname "$0")/../.." 
+. ./ci/sub/lib.sh
+
+cat >./install.sh <<EOF
+#!/bin/sh
+set -eu
+
+# *************
+# DO NOT EDIT
+#
+# install.sh was bundled together from
+#
+# - ./ci/sub/lib/rand.sh
+# - ./ci/sub/lib/log.sh
+# - ./ci/sub/lib/flag.sh
+# - ./ci/release/_install.sh
+#
+# The last of which implements the installation logic.
+#
+# Generated by ./ci/release/gen_install.sh.
+# *************
+EOF
+
+# sed removes the sourcing dependency lines as we're bundled everything into a single
+# script.
+sh_c cat \
+  ./ci/sub/lib/rand.sh \
+  ./ci/sub/lib/log.sh \
+  ./ci/sub/lib/flag.sh \
+  ./ci/release/_install.sh \
+  | sed '/^\. /d' >> ./install.sh