build: pin brightnessctl in a persistent local Gentoo overlay

image/overlay/sys-apps/brightnessctl/brightnessctl-0.5.1.ebuild

@@ -0,0 +1,18 @@
+# HydraOS local package for the pinned Gentoo snapshot.
+EAPI=8
+inherit toolchain-funcs udev
+DESCRIPTION="Read and control backlight brightness without privileged launchers"
+HOMEPAGE="https://github.com/Hummer12007/brightnessctl"
+SRC_URI="https://github.com/Hummer12007/brightnessctl/archive/refs/tags/${PV}.tar.gz -> ${P}.tar.gz"
+LICENSE="MIT"
+SLOT="0"
+KEYWORDS="amd64"
+RDEPEND="virtual/udev"
+src_compile() {
+    emake CC="$(tc-getCC)" VERSION="${PV}"
+}
+src_install() {
+    # Upstream's udev mode uses 0755, never its alternate setuid mode.
+    emake DESTDIR="${D}" PREFIX="${EPREFIX}/usr" UDEVDIR="${EPREFIX}$(get_udevdir)/rules.d" INSTALL_UDEV_RULES=1 install
+    dodoc README.md LICENSE
+}