Use spdlog for logging in Gloo

Change Gloo logging macros to use SPDLOG_* macros for logging. This
change is largely mechanical - changing the structure of the logging
calls to use fmtlib::fmt-style formatting. For example:
    GLOO_DEBUG("thingOne=", thingOne, " thingTwo=", thingTwo);
becomes:
    GLOO_DEBUG("thingOne={} thingTwo={}", thingOne, thingTwo);

However, there are also some less mechanical changes:
- Since we don't want to expose spdlog as a public dependency of Gloo,
   the logging infrastructure is moved into a different header
   (gloo/common/log.h). This header is not included in GLOO_HDRS, so it
   is not installed. It should only ever be included by .cc files, or
   non-public headers.
- Due to the previous change, the GLOO_ENFORCE_* macros are moved into
   a separate header (gloo/common/enforce.h). These are used often in
   public header files, and are not inherently tied to the logging, so
   this made the most sense.
- gloo/common/log.h (effectively renamed from logging.h) no longer needs
   a .cc file, as it just passes GLOO_* macros through to the SPDLOG_*
   macros.
- gloo has no init function which must be called first, and can be built
   as a static library (precluding something like
   __attribute__((constructor))). For this reason, all logger calls are
   prefixed with a std::run_once which ensures the logger init/config is
   performed before the first use of the logger.
- gloo/transport/tcp/debug_logger.{h,cc} are deleted, and replaced with
   a custom fmt formatter implementation in gloo/transport/debug_data.h.
- Wherever lists of includes were touched as part of this change, they
   were reformatted/fixed (e.g. X.h -> cX, alphabetical re-ordering,
   changing gloo includes from <> to "").

Author: jackbondpreston-arm

docs/errors.md

@@ -18,4 +18,4 @@ extend `::gloo::Exception`.
 ## Assertions
 Gloo asserts unexpected errors and logical invariants instead of expecting
 callers to handle them. `GLOO_ENFORCE` macros are defined in
-[`logging.h`](../gloo/common/logging.h)
+[`enforce.h`](../gloo/common/enforce.h)

gloo/algorithm.cc

@@ -8,7 +8,7 @@
 
 #include "gloo/algorithm.h"
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 
 namespace gloo {
 

gloo/allgather.cc

@@ -11,7 +11,7 @@
 #include <array>
 #include <cstring>
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/types.h"
 
 namespace gloo {

gloo/allgatherv.cc

@@ -11,7 +11,7 @@
 #include <cstring>
 #include <numeric>
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/types.h"
 
 namespace gloo {

gloo/allreduce.cc

@@ -12,7 +12,7 @@
 #include <array>
 #include <cstring>
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/math.h"
 #include "gloo/types.h"
 

gloo/alltoall.cc

@@ -10,7 +10,7 @@
 
 #include <cstring>
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/types.h"
 
 namespace gloo {

gloo/alltoall.h

@@ -8,7 +8,7 @@
 
 #pragma once
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/context.h"
 #include "gloo/transport/unbound_buffer.h"
 

gloo/alltoallv.cc

@@ -11,7 +11,7 @@
 #include <cstring>
 #include <numeric>
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/types.h"
 
 namespace gloo {

gloo/alltoallv.h

@@ -8,7 +8,7 @@
 
 #pragma once
 
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/context.h"
 #include "gloo/transport/unbound_buffer.h"
 

gloo/benchmark/cuda_main.cc

@@ -11,7 +11,7 @@
 
 #include "gloo/benchmark/benchmark.h"
 #include "gloo/benchmark/runner.h"
-#include "gloo/common/logging.h"
+#include "gloo/common/enforce.h"
 #include "gloo/cuda_allreduce_bcube.h"
 #include "gloo/cuda_allreduce_halving_doubling.h"
 #include "gloo/cuda_allreduce_halving_doubling_pipelined.h"