docs: Update build.md: HSA_OVERRIDE_GFX_VERSION clarification (#21331)

The `HSA_OVERRIDE_GFX_VERSION` variable can be used in ROCm to override an unsupported target architecture with a similar but supported target architecture.

This does not and has never worked on Windows. I think the clarification could avoid driving Windows people towards this solution that does not work.

diff --git a/docs/build.md b/docs/build.md
index ef086ff43493232359a4a42861c856bae749c1e3..616a838def973d12793b799ec6d65623a502ec69 100644 (file)
--- a/docs/build.md
+++ b/docs/build.md
@@ -389,7 +389,7 @@ You can download it from your Linux distro's package manager or from here: [ROCm
 
 
 The environment variable [`HIP_VISIBLE_DEVICES`](https://rocm.docs.amd.com/en/latest/understand/gpu_isolation.html#hip-visible-devices) can be used to specify which GPU(s) will be used.
-If your GPU is not officially supported you can use the environment variable [`HSA_OVERRIDE_GFX_VERSION`] set to a similar GPU, for example 10.3.0 on RDNA2 (e.g. gfx1030, gfx1031, or gfx1035) or 11.0.0 on RDNA3.
+If your GPU is not officially supported you can use the environment variable [`HSA_OVERRIDE_GFX_VERSION`] set to a similar GPU, for example 10.3.0 on RDNA2 (e.g. gfx1030, gfx1031, or gfx1035) or 11.0.0 on RDNA3. Note that [`HSA_OVERRIDE_GFX_VERSION`] is [not supported on Windows](https://github.com/ROCm/ROCm/issues/2654)
 
 ### Unified Memory