Improve & rename plugin sourcing function

Rename `plugin-load` to `source-plugin` and add a check for the plugin
directory, a message is displayed if it does not exist.

zshenv

@@ -21,9 +21,6 @@ PATH=$HOME/.local/bin:$PATH
 MANPATH=$HOME/.local/share/man:$MANPATH
 INFOPATH=$HOME/.local/share/info:$INFOPATH
 
-# Add ccache to the PATH if present
-[ -f /usr/bin/ccache ] && PATH=/usr/lib/ccache:$PATH
-
 # Use ~/.local for pip installs on macOS
 [ "`uname`" = "Darwin" ] && export PYTHONUSERBASE=$HOME/.local
 

zshrc

@@ -2,10 +2,14 @@
 # executing commands, will be sourced when starting as an interactive shell.
 
 # Load plugin scripts
-plugin-load() { source ~/.config/zsh/$1/$1.plugin.zsh }
-plugin-load zsh-autosuggestions
-plugin-load zsh-history-substring-search
-plugin-load zsh-syntax-highlighting
+source-plugin() {
+  [ -d ~/.config/zsh/$1 ] && \
+    source ~/.config/zsh/$1/$1.plugin.zsh || \
+    echo "zsh plugin not found: $1"
+}
+source-plugin zsh-autosuggestions
+source-plugin zsh-history-substring-search
+source-plugin zsh-syntax-highlighting
 
 # Disable non end-of-line autosuggest accept widgets
 ZSH_AUTOSUGGEST_ACCEPT_WIDGETS=(end-of-line vi-end-of-line)
@@ -117,22 +121,40 @@ typeset -U PATH
 typeset -U MANPATH
 typeset -U INFOPATH
 
+# Add ccache symlink directory to start of PATH, this must be after
+# `typeset -U PATH` because on macOS this reorders the list so ccache's
+# symlinks will no longer be at the start of PATH rendering it unusable.
+if [ `uname` = Darwin ]; then
+  [ -f /usr/local/bin/ccache ] && \
+    PATH=/usr/local/opt/ccache/libexec:$PATH
+else
+  [ -f /usr/bin/ccache ] && \
+    PATH=/usr/lib/ccache:$PATH
+fi
+
 # Aliases
 alias grep='grep --color=always'
-alias cninja='cmake -GNinja -DCMAKE_EXPORT_COMPILE_COMMNADS=ON'
-alias ssh='TERM=xterm-256color ssh'
+which cmake &> /dev/null && \
+  alias cninja='cmake -GNinja -DCMAKE_EXPORT_COMPILE_COMMNADS=ON'
+which ssh &> /dev/null && \
+  alias ssh='TERM=xterm-256color ssh'
 
 case `uname` in
   Linux)
     [ "$TMUX" = "" ] && \
-      alias cls="printf '\ec'" || alias cls="clear && printf '\e[3J'"
+      alias cls="printf '\ec'" || \
+      alias cls="clear && printf '\e[3J'"
     alias ls='ls -F --color=auto'
-    alias debug='cgdb --args'
+    which cgdb &> /dev/null && \
+      alias debug='cgdb --args' || \
+      which gdb &> /dev/null && \
+        alias debug='gdb --args'
     ;;
   Darwin)
     alias cls="clear && printf '\e[3J'"
     alias ls='ls -GFh'
-    alias debug='lldb --'
+    which lldb &> /dev/null && \
+      alias debug='lldb --'
     ;;
 esac