feat: start ssh agent from .zlogin

.zprofile

@@ -0,0 +1,21 @@
+SSH_ENV="$HOME/.ssh/agent-environment"
+
+function start_agent {
+    echo "Initialising new SSH agent..."
+    /usr/bin/ssh-agent | sed 's/^echo/#echo/' >"$SSH_ENV"
+    echo succeeded
+    chmod 600 "$SSH_ENV"
+    . "$SSH_ENV" >/dev/null
+    /usr/bin/ssh-add;
+}
+
+# Source SSH settings, if applicable
+if [ -f "$SSH_ENV" ]; then
+    . "$SSH_ENV" >/dev/null
+    #ps $SSH_AGENT_PID doesn't work under Cygwin
+    ps -ef | grep $SSH_AGENT_PID | grep ssh-agent$ >/dev/null || {
+        start_agent
+    }
+else
+    start_agent
+fi