[Bug bootstrap/105831] Nonportable syntax in "test" and "[" commands.

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105831

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The == syntax also fails with dash, which is used as the default /bin/sh on
debian:

$ /bin/sh -c "test foo = foo && echo y"
y
$ /bin/sh -c "test foo == foo && echo y"
/bin/sh: 1: test: foo: unexpected operator