The ACML_ROOT variable was being clobbered even if the user passed
in a valid value for ACML_ROOT through the command line.  Removed
the overwrite statement and instead added the ACML_ROOT environment
variable to the HINTS section of find_library().

Also, added a new location on Linux to find the dependant clBLAS.so
library, for the packaging step.
Merge remote-tracking branch 'upstream/develop' into develop
update