zsh: Remove zshenv

The code conditionally sourcing zprofile moved to the generated .zshenv
zsh/zshenv was otherwise empty and is now one file less zsh has to open on
startup.

install needs to be re-run to update the generated .zshenv

install

@@ -161,7 +161,8 @@ color 32 echo "  Writing .zshenv"
 generate "$HOME/.zshenv" <<EOF
 export DOTFILES="\$HOME/$(relpath "$DOT" "$HOME")"
 ZDOTDIR="\$DOTFILES/zsh"
-source "\$ZDOTDIR/zshenv"
+[[ -f "\$ZDOTDIR/zshenv" ]] && source "\$ZDOTDIR/zshenv"
+[[ ! -o LOGIN && "\$SHLVL" == 1 && -f "\$ZDOTDIR/zprofile" ]] && source "\$ZDOTDIR/zprofile"
 EOF
 
 for file in zshrc zpreztorc zlogin zlogout zprofile; do

zsh/zprofile

@@ -1,25 +1,20 @@
 # vim: ft=zsh
 #
-# Executes commands in every top-level shell
+# Executes commands in every top-level or login shell
 #
-# ATTENTION: This differs from usual zsh behaviour!
-#            Treat this file as a per-session zshenv instead.
+# ATTENTION: This differs from usual zsh behaviour! In addition to traditional
+#            login shells, this is also sourced by any top-level ($SHLVL=1)
+#            non-login shells. (In the latter case, from zshenv)
 #
-# Why is this useful? Because it only gets executed once for any given tree
-# of zsh-processes. You can use it to do environment computations that would
-# be too expensive for zshenv.
+# This is useful because it only gets executed once for any given tree
+# of zsh-processes, saving resources on sub-shell invocation while still
+# providing a consistent environment in login and non-login shells.
 #
 # Then why also source it in non-interactive shells?
 # Because it prevents desync between scripts and interactive prompts.
 # Ever tried to debug a script and ended up with "But it works in the prompt!"?
 #
-# That is especially true with X11-Scenarios, since a display-manager usually
-# doesn't source any profile. Which will lead to shells without a login shell in
-# their parent process tree, which means the profile is basically useless.
-#
-# If you need loginshell-only commands, use zlogin instead. If you insist on
-# zprofile, create a .zprofile (note the dot) file in this directory and zsh will
-# treat it as always.
+# For code intended for login shells only, use zlogin instead.
 #
 
 #

zsh/zshenv

@@ -1,11 +0,0 @@
-#
-# Defines environment variables.
-#
-# Authors:
-#   Sorin Ionescu <sorin.ionescu@gmail.com>
-#
-
-# Source the profile on every top-level shell
-if [[ "$SHLVL" -eq 1 && ! -o LOGIN ]]; then
-  source "$DOTFILES/zsh/zprofile"
-fi