BLD: enable building NumPy with Meson

This enables building with NumPy on Linux and macOS. Windows support
should be complete to, but is untested as of now and may need a few
tweaks. This contains:
- A set of `meson.build` files and related code generation script
  tweaks, header templates, etc.
- One CI job on Linux
- Basic docs on using Meson to build NumPy (not yet integrated in the
  html docs, it's too early for that - this is for early adopters right
  now).

The build should be complete, with the major exception of SIMD support.
The full test suite passes. See gh-22546 for the tracking issue with
detailed notes on the plan for switching NumPy to Meson as its build
system.

Co-authored-by: Stefan van der Walt <stefanv@berkeley.edu>

1 files changed, 40 insertions, 0 deletions

diff --git a/generate_version.py b/generate_version.py
new file mode 100644
index 000000000..b3c8a3978
--- /dev/null
+++ b/generate_version.py
@@ -0,0 +1,40 @@
+# Note: This file has to live next to versioneer.py or it will not work
+import argparse
+import os
+
+import versioneer
+
+
+def write_version_info(path):
+    vinfo = versioneer.get_versions()
+    full_version = vinfo['version']
+    git_revision = vinfo['full-revisionid']
+
+    if os.environ.get("MESON_DIST_ROOT"):
+        path = os.path.join(os.environ.get("MESON_DIST_ROOT"), path)
+
+    with open(path, "w") as f:
+        f.write("def get_versions():\n")
+        f.write("    return {\n")
+        f.write(f"        'full-revisionid': '{git_revision}',\n")
+        f.write(f"        'version': '{full_version}'\n")
+        f.write("}")
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-o", "--outfile", type=str, help="Path to write version info to"
+    )
+    args = parser.parse_args()
+
+    if not args.outfile.endswith(".py"):
+        raise ValueError(
+            f"Output file must be a Python file. "
+            f"Got: {args.outfile} as filename instead"
+        )
+
+    write_version_info(args.outfile)
+
+
+main()