Store cache files in a user-writable location

Fixes #1122

modules/fasd/init.zsh

@@ -19,7 +19,7 @@ fi
 # Initialization
 #
 
-cache_file="${0:h}/cache.zsh"
+cache_file="${TMPDIR:-/tmp}/prezto-fasd-cache.$UID.zsh"
 if [[ "${commands[fasd]}" -nt "$cache_file" || ! -s "$cache_file"  ]]; then
   # Set the base init arguments.
   init_args=(zsh-hook)

modules/node/init.zsh

@@ -30,7 +30,7 @@ fi
 
 # Load NPM completion.
 if (( $+commands[npm] )); then
-  cache_file="${0:h}/cache.zsh"
+  cache_file="${TMPDIR:-/tmp}/prezto-node-cache.$UID.zsh"
 
   if [[ "$commands[npm]" -nt "$cache_file" || ! -s "$cache_file" ]]; then
     # npm is slow; cache its output.

modules/perl/init.zsh

@@ -39,7 +39,7 @@ fi
 
 if [[ "$OSTYPE" == darwin* ]]; then
   # Perl is slow; cache its output.
-  cache_file="${0:h}/cache.zsh"
+  cache_file="${TMPDIR:-/tmp}/prezto-perl-cache.$UID.zsh"
   perl_path="$HOME/Library/Perl/5.12"
 
   if [[ -f "$perl_path/lib/perl5/local/lib.pm" ]]; then

modules/python/init.zsh

@@ -129,7 +129,7 @@ fi
 
 # Load PIP completion.
 if (( $#commands[(i)pip(|[23])] )); then
-  cache_file="${0:h}/cache.zsh"
+  cache_file="${TMPDIR:-/tmp}/prezto-python-cache.$UID.zsh"
 
   # Detect and use one available from among 'pip', 'pip2', 'pip3' variants
   pip_command="$commands[(i)pip(|[23])]"