Support toolkit_path in rules_cuda_dependencies (#121)

cuda/private/repositories.bzl

@@ -50,7 +50,7 @@ def detect_cuda_toolkit(repository_ctx):
 
             # Some distributions instead put CUDA binaries in a seperate path
             # Manually check and redirect there when necessary
-            alternative = repository_ctx.path('/usr/lib/nvidia-cuda-toolkit/bin/nvcc')
+            alternative = repository_ctx.path("/usr/lib/nvidia-cuda-toolkit/bin/nvcc")
             if str(ptxas_path) == "/usr/bin/ptxas" and alternative.exists:
                 ptxas_path = alternative
             cuda_path = str(ptxas_path.dirname.dirname)
@@ -206,8 +206,12 @@ local_cuda = repository_rule(
     # remotable = True,
 )
 
-def rules_cuda_dependencies():
-    """Populate the dependencies for rules_cuda. This will setup workspace dependencies (other bazel rules) and local toolchains."""
+def rules_cuda_dependencies(toolkit_path = None):
+    """Populate the dependencies for rules_cuda. This will setup workspace dependencies (other bazel rules) and local toolchains.
+
+    Args:
+        toolkit_path: Optionally specify the path to CUDA toolkit. If not specified, it will be detected automatically.
+    """
     maybe(
         name = "bazel_skylib",
         repo_rule = http_archive,
@@ -228,4 +232,4 @@ def rules_cuda_dependencies():
         ],
     )
 
-    local_cuda(name = "local_cuda")
+    local_cuda(name = "local_cuda", toolkit_path = toolkit_path)