DOC: Some notes on CUDA builds

README.md

@@ -16,3 +16,19 @@ Prior to FSL 6.1.X, the contents of this project were provided by the
 The `.ci` directory contains a collection of tests which validate the
 behaviour of various aspects of the `base` project. All tests are written
 in Python, and are executed with `pytest`.
+
+## CUDA build options
+
+The following options may be used to control compilation of a  CUDA project:
+
+ - `CUDA_HOME`:    Specify the path to the CUDA installation directory
+ - `CUDA_STATIC`:  Statically link against the CUDA runtime and certain;
+                  CUDA Toolkit libraris (default is to use dynamic linking).
+ - `GENCODEFLAGS`: `-gencode` options specifying the device architectures to
+                  compile device code for (default is to use the
+                  `config/supportedGencodes.sh` script).
+
+For example, to compile a CUDA project with a specific CUDA installation, and
+using static linking:
+
+    make CUDA_STATIC=1 CUDA_HOME=/usr/local/cuda-10.1