[#295]:svarga:build, honor CMP0074 so examples find_package respects HDF5_ROOT

[steven-varga]

Closes #295.

Problem

A CMake dev warning at configure (surfaced by the BUILD_EXAMPLES=ON default, #278):

CMake Warning (dev) at examples/CMakeLists.txt:27 (find_package):
  Policy CMP0074 is not set ... CMake is ignoring the variable HDF5_ROOT

examples/CMakeLists.txt declares cmake_minimum_required(VERSION 3.10), which predates CMP0074 (3.12). Under that baseline the policy defaults to OLD, so find_package(HDF5) ignores the HDF5_ROOT the file builds (lines 20-25) for custom HDF Group installs — the discovery logic was silently inert.

Fix

cmake_policy(SET CMP0074 NEW) after project() (guarded with if(POLICY ...)).

Verification

Configure with HDF5_ROOT set: 0 CMP0074 warnings, 0 CMake warnings, HDF5 found, no "ignoring the variable" message.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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