Use absolute path when executing 'uname'

The first 'uname' command found in the PATH may not be the system
supplied 'uname', and may lead to generating unexpected CPU types for
UPLIDS. This is particular true if GNU coretuils is installed on an AIX
system.
Initial check-in of bde_verify to this repository.
Updated for github release.
Merge branch 'master' of devgit:bde/bde-oss-tools
Fixed configure for sa packages.
Merge remote-tracking branch 'remotes/origin/review/bde_verify-initial'