configure: portability fixes - take 2

It is useful to sometime run on a strictly POSIX-compliant
shell... :-/

And it is sometime interesting to refresh Q-patches before
finishing the series... :-(

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="dsreed on freenode/#crosstool-ng"

 reporter_url=""

 reporter_comment="Enables experimental support for VFP/NEON hardware floating point."