Wei Liu writes ("[PATCH] m4: use test instead of []"):
> It is reported that [] was removed by autoconf, which caused the
> following error:
>
> ./configure: line 4681: -z: command not found
>
> Switch to test. That's what is used throughout our configure scripts.
The reason for [ ] being removed is that configure.ac et al are
processed by m4 with quote characters set to [ ].
> APPEND_LDFLAGS="$APPEND_LDFLAGS -L$ldflag"
> done
> -if [ ! -z $EXTRA_PREFIX ]; then
> +if test ! -z $EXTRA_PREFIX ; then
> CPPFLAGS="$CPPFLAGS -I$EXTRA_PREFIX/include"
If $EXTRA_PREFIX contains nothing (or just whitespace) this expands to
test ! -z
which only works by accident. It is parsed ax
if not (string_is_nonempty("-z"))
Variable expansions in test expressions should generally be in " ".
Ian.
