[Bug target/66136] AArch64 geniterators.sh relies on GNU sed syntax, causing build failure on FreeBSD and probably Mac

[nszabolcs at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66136

--- Comment #5 from Szabolcs Nagy <nszabolcs at gmail dot com> ---
patch that uses awk:
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01578.html