Add information about the verbose option in .bazelrc

Author: mhucka

docs/bazel.md

@@ -16,13 +16,16 @@ requires the circuit file to be specified both on the command line and in the
 bazel run --config=avx --config=openmp apps:qsim_base -- -c circuits/circuit_q24
 ```
 
-## Build configs
+## Build configurations
 
 Depending on the optimizers available on your machine, different config flags
 (such as `--config=avx`, above) can be set to control which optimizers are
 included in a given build or test run.
 
-Vector arithmetic optimizers (pick one at most):
+### Vector arithmetic optimizers
+
+Pick at most one of the following options:
+
 ```
 # Use AVX instructions for vector arithmetic.
 --config=avx
@@ -34,7 +37,10 @@ Vector arithmetic optimizers (pick one at most):
 --config=basic
 ```
 
-Parallelism optimizers (pick one at most):
+### Parallelism optimizers
+
+Pick at most one of the following options:
+
 ```
 # Use OpenMP to run operations in parallel when possible.
 --config=openmp
@@ -43,11 +49,26 @@ Parallelism optimizers (pick one at most):
 --config=nopenmp
 ```
 
-Memory allocation (pick one at most):
+### Memory allocators
+
+
+[TCMalloc](https://github.com/google/tcmalloc) is a fast, multithreaded
+implementation of C's `malloc()` and C++'s `new` operator. It is an independent
+open-source library developd by Google. TCMalloc can be used with qsim as an
+alternative to the default `malloc()`. Pick at most one of the following
+options:
+
 ```
-# Use tcmalloc for memory allocation.
+# Use TCMalloc for memory allocation.
 --config=tcmalloc
 
 # Use malloc for memory allocation (default).
 --config=malloc
 ```
+
+### Additional configuration options
+
+To provide more information when building and testing qsim, you can add the
+configuration option `--config=verbose` to any of the `bazel`  commands above.
+
+Other configuration options are described elsewhere in the qsim documentation.