configure.ac: Fix bashisms

[thesamesam]

configure scripts need to be runnable with a POSIX-compliant /bin/sh.

On many (but not all!) systems, /bin/sh is provided by Bash, so errors like this aren't spotted. Notably Debian defaults to /bin/sh provided by dash which doesn't tolerate such bashisms as '=='.

This retains compatibility with bash.

Signed-off-by: Sam James sam@gentoo.org

[knet-ci-bot]

Can one of the admins verify this patch?

[fabbione]

ok to test

[fabbione]

@thesamesam good catch, thanks for the patch.

[thesamesam]

thanks!