rust fails to build linter ppc64le

README.md

@@ -220,6 +220,35 @@ Such as:
 * Documentation system, perhaps Sphinx or something else SOTA.
 * Build system, probably hatch.
 * Push to PyPI test server.
+* Also re-build on ppc64le.
+* Linter, such as ruff. Ruff fails on ppc64le with page size /
+  memory allocation error (Debian kernel).
+
+
+# Linter
+Ruff is a linter only needed for "development", not for
+running the software.
+
+Ruff pip install fails on ppc64le with page size /
+memory allocation error (Debian kernel).
+
+To (re-)build ruff under ppc64le, such as (XXX fail):
+
+```
+sudo apt install rustc
+virtualenv env
+source env/bin/activate
+pip install -U setuptools wheel pip
+pip install maturin clap
+pip install --ignore-installed --no-binary :all: ruff
+```
+
+Building Ruff requires building maturin.
+Maturin requires rustc 1.64, but Debian Bookworm has 1.63.0,
+so the version of Rust in Debian is too old to build Maturin.
+Building an older Maturin just causes other build dependency
+failures on ppc64le. Rust programs fail to build from scratch
+on ppc64le often, unfortunately.
 
 
 # Upstream