* Rearrange CMakefile
* Enable linking to external rocshmem library
* Minor fix for the functional test driver
* ROCSHMEM_HOME detection fixed
[ROCm/rocshmem commit: 96424a59a8]
* add backend_ipc.{cpp & hpp}
* rename context_ipc.{cpp & hpp} to context_ipc_device.{cpp & hpp}
* add host interface to IPC backend
* add context_ipc_host.{cpp & hpp} to support host interface
* add USE_RO compile flag to enable support for single backend interface at a time
* add ipc_single script to build rocSHMEM with IPC backend
[ROCm/rocshmem commit: 49779863c2]