QPID-5476: Improve the robustness and portability of check-abi
- Fix check-abi for BSD mktemp/sed command line syntax.
- Make sure we fix sort to C locale to avoid any confusion.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1558201 13f79535-47bb-0310-9956-ffa450edef68