[tools, cmake] refactor: update/hash check scripts, use tags for some more deps, proper CPMUtil separation (#2666)

Uses tags for a bunch of deps that can use them

Also adds a bunmch of scripts to tools/cpm, notably for checking hashes
and checking for updates.

TODO for the future:
- CI target to check hashes
- Weekly CI to check for updates

Need to get that other CI runner up

additional stuff

- Ports gentoo fixes
- makes solaris work (TODO: sdl2)
- way better docs
- properly separates CPMUtil as a standalone project

Reviewed-on: #2666
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

tools/cpm/common.sh

@@ -0,0 +1,32 @@
+#!/bin/sh -e
+
+# SPDX-FileCopyrightText: 2025 crueter
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+##################################
+# CHANGE THESE FOR YOUR PROJECT! #
+##################################
+
+# Which directories to search
+DIRS=". src"
+
+# How many levels to go (3 is 2 subdirs max)
+MAXDEPTH=3
+
+# shellcheck disable=SC2038
+# shellcheck disable=SC2016
+# shellcheck disable=SC2086
+[ -z "$PACKAGES" ] && PACKAGES=$(find $DIRS -maxdepth "$MAXDEPTH" -name cpmfile.json | xargs jq -s 'reduce .[] as $item ({}; . * $item)')
+
+# For your project you'll want to change the PACKAGES call to include whatever locations you may use (externals, src, etc.)
+# Always include .
+LIBS=$(echo "$PACKAGES" | jq -j 'keys_unsorted | join(" ")')
+
+export PACKAGES
+export LIBS
+export DIRS
+export MAXDEPTH
+
+value() {
+	echo "$JSON" | jq -r ".$1"
+}