Unify environment variable management (#235)

* Add environment variable configuration infrastructure
  - Namespace rocshmem::envvar
  - Track all config env vars in per-category lists
  - Remove duplicates from list of allowed env var types
  - Reject negative inputs for unsigned integer types
  - Accept empty strings for std::string
  - Print error source location using C++20 std::source_location
  - Unit tests
* Port environment variables
  - ROCSHMEM_UNIQUEID_WITH_MPI
  - ROCSHMEM_RO_DISABLE_IPC
  - ROCSHMEM_BOOTSTRAP_TIMEOUT
  - ROCSHMEM_BOOTSTRAP_HOSTID
  - ROCSHMEM_BOOTSTRAP_SOCKET_IFNAME
  - ROCSHMEM_RO_PROGRESS_DELAY
  - ROCSHMEM_BOOTSTRAP_SOCKET_FAMILY
  - ROCSHMEM_MAX_NUM_CONTEXTS
    + Merge the independent per-backend copies into a single variable
      that is used by all three backends (IPC, RO, GDA).
    + Set default to 32 (for GDA); prior default for IPC and RO was 1024.
  - ROCSHMEM_MAX_NUM_HOST_CONTEXTS
  - ROCSHMEM_MAX_WF_BUFFERS
  - ROCSHMEM_SQ_SIZE
  - ROCSHMEM_RO_NET_CPU_QUEUE
    + Renamed from RO_NET_CPU_QUEUE
    + Change env var input type to bool, default to false
    + Invert code logic: setting RO_NET_CPU_QUEUE to anything
      would /disable/ a variable gpu_queue, which defaulted to true.
      Variable is now named config::ro::net_cpu_queue,
      with all prior checks for gpu_queue inverted.
  - ROCSHMEM_USE_IB_HCA
  - ROCSHMEM_HEAP_SIZE
    + Defaults to 1L << 30 i.e. 1 GiB,
      from default heap size in memory/heap_memory.hpp.
  - ROCSHMEM_MAX_NUM_TEAMS
    + Unlike other env vars, this can be referenced from devices.
    + Function currently narrows from size_t to int: uses need to be audited
      for safety and correctness in using size_t directly.
  - ROCSHMEM_GDA_ALTERNATE_QP_PORTS
* New env var ROCSHMEM_DEBUG
  - Debug levels:
    + NONE
    + VERSION
    + WARN
    + INFO
    + TRACE
  - Currently unused - will be added later
  - Mirrors RCCL debug control
* Remove rocshmem::rocshmem_env_config
* Change interface for GetClosestNicToGpu
  to accept const char** instead of char**:
  the pointed-to string does not need to be modified
  - Files were not audited for inclusion of util.hpp only for env vars
---------
Signed-off-by: Omri Mor <Omri.Mor@amd.com>

src/rocshmem.cpp

@@ -35,6 +35,7 @@
 
 #include "backend_bc.hpp"
 #include "context_incl.hpp"
+#include "envvar.hpp"
 #if defined(USE_GDA)
 #include "gda/backend_gda.hpp"
 #include "gda/context_gda_tmpl_host.hpp"
@@ -229,9 +230,9 @@ rocshmem_ctx_t ROCSHMEM_HOST_CTX_DEFAULT;
     assert (attr->rank < attr->nranks);
 
     bootstr = new TcpBootstrap(attr->rank, attr->nranks);
-    bootstr->initialize(attr->uid, rocshmem_env_.get_bootstrap_timeout());
+    bootstr->initialize(attr->uid, envvar::bootstrap::timeout);
 
-    if (rocshmem_env_.get_uniqueid_with_mpi() ) {
+    if (envvar::uniqueid_with_mpi) {
       library_init_subcomm(bootstr, attr->nranks, attr->rank);
     } else {
       library_init (bootstr);