[Fix sorin-ionescu#171] Background non-session affecting code

templates/zlogin

@@ -5,20 +5,21 @@
 #   Sorin Ionescu <sorin.ionescu@gmail.com>
 #
 
-# Compile the completion dump to increase startup speed.
-dump_file="$HOME/.zcompdump"
-if [[ "$dump_file" -nt "${dump_file}.zwc" || ! -s "${dump_file}.zwc" ]]; then
-  zcompile "$dump_file"
-fi
-unset dump_file
+# Execute code that does not affect the current session in the background.
+{
+  # Compile the completion dump to increase startup speed.
+  dump_file="$HOME/.zcompdump"
+  if [[ "$dump_file" -nt "${dump_file}.zwc" || ! -s "${dump_file}.zwc" ]]; then
+    zcompile "$dump_file"
+  fi
 
-# Set environment variables for launchd processes.
-if [[ "$OSTYPE" == darwin* ]]; then
-  for env_var in PATH MANPATH; do
-    launchctl setenv "$env_var" "${(P)env_var}" &!
-  done
-  unset env_var
-fi
+  # Set environment variables for launchd processes.
+  if [[ "$OSTYPE" == darwin* ]]; then
+    for env_var in PATH MANPATH; do
+      launchctl setenv "$env_var" "${(P)env_var}"
+    done
+  fi
+} &!
 
 # Print a random, hopefully interesting, adage.
 if (( $+commands[fortune] )); then