treewide: Fix unsafe concatenation of $LD_LIBRARY_PATH

Naive concatenation of $LD_LIBRARY_PATH can result in an empty
colon-delimited segment; this tells glibc to load libraries from the
current directory, which is definitely wrong, and may be a security
vulnerability if the current directory is untrusted.  (See #67234, for
example.)  Fix this throughout the tree.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

pkgs/games/dwarf-fortress/wrapper/dfhack.in

@@ -7,5 +7,5 @@ for i in dfhack.init-example dfhack-config/default hack/* stonesense/*; do
 done
 
 cd "$DF_DIR"
-LD_LIBRARY_PATH="$env_dir/hack/libs:$env_dir/hack:$LD_LIBRARY_PATH" \
+LD_LIBRARY_PATH="$env_dir/hack/libs:$env_dir/hack${LD_LIBRARY_PATH:+:}$LD_LIBRARY_PATH" \
   LD_PRELOAD="$env_dir/hack/libdfhack.so:$LD_PRELOAD" exec $env_dir/libs/Dwarf_Fortress "$@"