do it my way, modernize cmake

build dynamic lib
use makefile wrapper to test all use cases
include clang-tidy config file
prevent clang-tidy warnings

GNUmakefile

@@ -0,0 +1,58 @@
+#
+# CURDIR=$(/bin/pwd)
+#
+# GENERATOR="Unix Makefiles"
+GENERATOR=Ninja
+
+export CPM_SOURCE_CACHE=${HOME}/.cache/CPM
+export CPM_USE_LOCAL_PACKAGES=1
+
+.PHONY: update format all test check clean distclean lock
+
+# the default target does just all
+check: all
+
+all: test
+
+test: install
+
+
+distclean:
+	rm -rf build root
+
+# update CPM.cmake
+update:
+	wget -q -O cmake/CPM.cmake https://github.com/cpm-cmake/CPM.cmake/releases/latest/download/get_cpm.cmake
+
+lock: install
+	cmake --build build/install --target cpm-update-package-lock
+
+# install the library
+install:
+	cmake -S . -B build/install -G "${GENERATOR}" -DCMAKE_PREFIX_PATH=${CURDIR}/root -DCMAKE_INSTALL_PREFIX=${CURDIR}/root -DCMAKE_CXX_STANDARD=20 # --trace-expand
+	cmake --build build/install --target install
+
+# test the library
+test:
+	cmake -S test -B build/test -G "${GENERATOR}" -DCMAKE_PREFIX_PATH=${CURDIR}/root -DTEST_INSTALLED_VERSION=1
+	cmake --build build/test
+	cmake --build build/test --target test
+
+# all together
+all:
+	cmake -S all -B build/all -G "${GENERATOR}" -DCMAKE_PREFIX_PATH=${CURDIR}/root -DTEST_INSTALLED_VERSION=1 -DENABLE_TEST_COVERAGE=1
+	cmake --build build/all
+	cmake --build build/all --target test
+	cmake --build build/all --target GenerateDocs
+	cmake --build build/all --target check-format
+
+format: distclean
+	find . -name CMakeLists.txt | xargs cmake-format -i
+	find . -name '*.cpp' | xargs clang-format -i
+	find . -name '*.h' | xargs clang-format -i
+
+# check the library
+check:
+	cmake -S standalone -B build/standalone -G "${GENERATOR}" -DCMAKE_PREFIX_PATH=${CURDIR}/root -DCMAKE_EXPORT_COMPILE_COMMANDS=1
+	cmake --build build/standalone --target all
+	run-clang-tidy.py -p build/standalone -checks='-*,modernize-*,misc-*,hicpp-*,cert-*,readability-*,portability-*,performance-*,google-*' standalone