[clang] [llvm] [Clang] Add env var for nvptx-arch/amdgpu-arch timeout (PR #102521)

[Joseph Huber via cfe-commits]

================
@@ -99,7 +99,8 @@ def warn_drv_amdgpu_cov6: Warning<
   " use at your own risk">;
 def err_drv_undetermined_gpu_arch : Error<
   "cannot determine %0 architecture: %1; consider passing it via "
-  "'%2'">;
+  "'%2' or increasing the tool timeout using the environment variable "
+  "'CLANG_TOOL_CHAIN_PROGRAM_WAIT' (in secs, <=0 is inifinite)">;
----------------
jhuber6 wrote:

```suggestion
  "'CLANG_TOOLCHAIN_PROGRAM_WAIT' (in secs, <=0 is inifinite)">;
```

https://github.com/llvm/llvm-project/pull/102521