Update cache files when .zpreztorc file is modified

Fixes sorin-ionescu#1581

modules/fasd/init.zsh

@@ -20,7 +20,9 @@ fi
 #
 
 cache_file="${TMPDIR:-/tmp}/prezto-fasd-cache.$UID.zsh"
-if [[ "${commands[fasd]}" -nt "$cache_file" || ! -s "$cache_file"  ]]; then
+if [[ "${commands[fasd]}" -nt "$cache_file" \
+      || "${ZDOTDIR:-$HOME}/.zpreztorc" -nt "$cache_file" \
+      || ! -s "$cache_file"  ]]; then
   # Set the base init arguments.
   init_args=(zsh-hook)
 

modules/node/init.zsh

@@ -32,7 +32,9 @@ fi
 if (( $+commands[npm] )); then
   cache_file="${TMPDIR:-/tmp}/prezto-node-cache.$UID.zsh"
 
-  if [[ "$commands[npm]" -nt "$cache_file" || ! -s "$cache_file" ]]; then
+  if [[ "$commands[npm]" -nt "$cache_file" \
+        || "${ZDOTDIR:-$HOME}/.zpreztorc" -nt "$cache_file" \
+        || ! -s "$cache_file" ]]; then
     # npm is slow; cache its output.
     npm completion >! "$cache_file" 2> /dev/null
   fi

modules/perl/init.zsh

@@ -43,7 +43,7 @@ if [[ "$OSTYPE" == darwin* ]]; then
   perl_path="$HOME/Library/Perl/5.12"
 
   if [[ -f "$perl_path/lib/perl5/local/lib.pm" ]]; then
-    if [[ ! -s "$cache_file" ]]; then
+    if [[ "${ZDOTDIR:-$HOME}/.zpreztorc" -nt "$cache_file" || ! -s "$cache_file" ]]; then
       perl -I$perl_path/lib/perl5 -Mlocal::lib=$perl_path >! "$cache_file"
     fi
 

modules/python/init.zsh

@@ -149,7 +149,9 @@ if (( $#commands[(i)pip(|[23])] )); then
   # Detect and use one available from among 'pip', 'pip2', 'pip3' variants
   pip_command="$commands[(i)pip(|[23])]"
 
-  if [[ "$pip_command" -nt "$cache_file" || ! -s "$cache_file" ]]; then
+  if [[ "$pip_command" -nt "$cache_file" \
+        || "${ZDOTDIR:-$HOME}/.zpreztorc" -nt "$cache_file" \
+        || ! -s "$cache_file" ]]; then
     # pip is slow; cache its output. And also support 'pip2', 'pip3' variants
     $pip_command completion --zsh \
       | sed -e "s|compctl -K [-_[:alnum:]]* pip|& pip2 pip3|" >! "$cache_file" 2> /dev/null