zshrc: make sure to not alias already aliased ls commands

Thanks to Moviuro <moviuro+grml@gmail.com> for spotting,
thanks to Frank Terbeck <ft@grml.org> for reviewing.

etc/zsh/zshrc

@@ -2436,21 +2436,21 @@ fi
 # do we have GNU ls with color-support?
 if [[ "$TERM" != dumb ]]; then
     #a1# List files with colors (\kbd{ls -F \ldots})
-    alias ls='ls -F '${ls_options:+"${ls_options[*]}"}
+    alias ls='command ls -F '${ls_options:+"${ls_options[*]}"}
     #a1# List all files, with colors (\kbd{ls -la \ldots})
-    alias la='ls -la '${ls_options:+"${ls_options[*]}"}
+    alias la='command ls -la '${ls_options:+"${ls_options[*]}"}
     #a1# List files with long colored list, without dotfiles (\kbd{ls -l \ldots})
-    alias ll='ls -l '${ls_options:+"${ls_options[*]}"}
+    alias ll='command ls -l '${ls_options:+"${ls_options[*]}"}
     #a1# List files with long colored list, human readable sizes (\kbd{ls -hAl \ldots})
-    alias lh='ls -hAl '${ls_options:+"${ls_options[*]}"}
+    alias lh='command ls -hAl '${ls_options:+"${ls_options[*]}"}
     #a1# List files with long colored list, append qualifier to filenames (\kbd{ls -lF \ldots})\\&\quad(\kbd{/} for directories, \kbd{@} for symlinks ...)
-    alias l='ls -lF '${ls_options:+"${ls_options[*]}"}
+    alias l='command ls -lF '${ls_options:+"${ls_options[*]}"}
 else
-    alias ls='ls -F'
-    alias la='ls -la'
-    alias ll='ls -l'
-    alias lh='ls -hAl'
-    alias l='ls -lF'
+    alias ls='command ls -F'
+    alias la='command ls -la'
+    alias ll='command ls -l'
+    alias lh='command ls -hAl'
+    alias l='command ls -lF'
 fi
 
 alias mdstat='cat /proc/mdstat'
@@ -2960,35 +2960,35 @@ alias j='jobs -l'
 
 # listing stuff
 #a2# Execute \kbd{ls -lSrah}
-alias dir="ls -lSrah"
+alias dir="command ls -lSrah"
 #a2# Only show dot-directories
-alias lad='ls -d .*(/)'
+alias lad='command ls -d .*(/)'
 #a2# Only show dot-files
-alias lsa='ls -a .*(.)'
+alias lsa='command ls -a .*(.)'
 #a2# Only files with setgid/setuid/sticky flag
-alias lss='ls -l *(s,S,t)'
+alias lss='command ls -l *(s,S,t)'
 #a2# Only show symlinks
-alias lsl='ls -l *(@)'
+alias lsl='command ls -l *(@)'
 #a2# Display only executables
-alias lsx='ls -l *(*)'
+alias lsx='command ls -l *(*)'
 #a2# Display world-{readable,writable,executable} files
-alias lsw='ls -ld *(R,W,X.^ND/)'
+alias lsw='command ls -ld *(R,W,X.^ND/)'
 #a2# Display the ten biggest files
-alias lsbig="ls -flh *(.OL[1,10])"
+alias lsbig="command ls -flh *(.OL[1,10])"
 #a2# Only show directories
-alias lsd='ls -d *(/)'
+alias lsd='command ls -d *(/)'
 #a2# Only show empty directories
-alias lse='ls -d *(/^F)'
+alias lse='command ls -d *(/^F)'
 #a2# Display the ten newest files
-alias lsnew="ls -rtlh *(D.om[1,10])"
+alias lsnew="command ls -rtlh *(D.om[1,10])"
 #a2# Display the ten oldest files
-alias lsold="ls -rtlh *(D.Om[1,10])"
+alias lsold="command ls -rtlh *(D.Om[1,10])"
 #a2# Display the ten smallest files
-alias lssmall="ls -Srl *(.oL[1,10])"
+alias lssmall="command ls -Srl *(.oL[1,10])"
 #a2# Display the ten newest directories and ten newest .directories
-alias lsnewdir="ls -rthdl *(/om[1,10]) .*(D/om[1,10])"
+alias lsnewdir="command ls -rthdl *(/om[1,10]) .*(D/om[1,10])"
 #a2# Display the ten oldest directories and ten oldest .directories
-alias lsolddir="ls -rthdl *(/Om[1,10]) .*(D/Om[1,10])"
+alias lsolddir="command ls -rthdl *(/Om[1,10]) .*(D/Om[1,10])"
 
 # some useful aliases
 #a2# Remove current empty directory. Execute \kbd{cd ..; rmdir \$OLDCWD}