Removed the ?= operator in the Makefile. Non-GNU makes choke on this.
Removed the ?= operator in the Makefile. Non-GNU makes choke on this.

arm-hpc/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi