Zsh: replace $(id -u) with ${EUID}

Less subshells spawned.

.config/zsh/.zprofile

@@ -23,7 +23,7 @@ if command -v emacsclient > /dev/null; then
     else
         VISUAL="$(command -v emacs)"
     fi
-    if [[ $(id -u) -eq 0 ]]; then
+    if [[ ${EUID} -eq 0 ]]; then
         # Edit files as root in the Emacs instance run by the current user.
         VISUAL="$(command -v emacsremote) --sudo --local"
     fi
@@ -151,8 +151,8 @@ esac
 # Run SSH/GPG agents if they are installed and not already started. If they are
 # started, attempt to inherit them.
 if command -v keychain > /dev/null; then
-    if [[ $(pgrep --uid $(id -u) ssh-agent)
-        && $(pgrep --uid $(id -u) gpg-agent) ]]; then
+    if [[ $(pgrep --uid ${EUID} ssh-agent)
+        && $(pgrep --uid ${EUID} gpg-agent) ]]; then
         # Set environment variables from files.
         if [[ -z "${SSH_AUTH_SOCK}" ]]; then
             source "${HOME}/.keychain/$(hostname)-sh"
@@ -175,11 +175,11 @@ if command -v keychain > /dev/null; then
 else
     # keychain not installed, start SSH/GPG agents if they are not running.
     if command -v ssh-agent > /dev/null \
-            && [[ ! $(pgrep --uid $(id -u) ssh-agent) ]]; then
+            && [[ ! $(pgrep --uid ${EUID} ssh-agent) ]]; then
         eval $(ssh-agent -t 16H 2> /dev/null)
     fi
     if command -v gpg-agent > /dev/null \
-            && [[ ! $(pgrep --uid $(id -u) gpg-agent) ]]; then
+            && [[ ! $(pgrep --uid ${EUID} gpg-agent) ]]; then
         eval $(gpg-agent --daemon --quiet --default-cache-ttl $((60*16)) \
                          --max-cache-ttl $((60*16)))
     fi