sys-devel/clang-runtime: Add 20.0.0_pre20241106 snapshot

Signed-off-by: Michał Górny <mgorny@gentoo.org>

sys-devel/clang-runtime/clang-runtime-20.0.0_pre20241106.ebuild

@@ -0,0 +1,39 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit multilib-build toolchain-funcs
+
+DESCRIPTION="Meta-ebuild for clang runtime libraries"
+HOMEPAGE="https://clang.llvm.org/"
+
+LICENSE="metapackage"
+SLOT="${PV%%.*}"
+IUSE="+compiler-rt libcxx openmp +sanitize"
+REQUIRED_USE="sanitize? ( compiler-rt )"
+
+RDEPEND="
+	compiler-rt? (
+		~sys-libs/compiler-rt-${PV}:${SLOT}[abi_x86_32(+)?,abi_x86_64(+)?]
+		sanitize? (
+			~sys-libs/compiler-rt-sanitizers-${PV}:${SLOT}[abi_x86_32(+)?,abi_x86_64(+)?]
+		)
+	)
+	libcxx? ( >=sys-libs/libcxx-${PV}[${MULTILIB_USEDEP}] )
+	openmp? ( >=sys-libs/libomp-${PV}[${MULTILIB_USEDEP}] )
+"
+
+pkg_pretend() {
+	if tc-is-clang; then
+		ewarn "You seem to be using clang as a system compiler.  As of clang-16,"
+		ewarn "upstream has turned a few warnings that commonly occur during"
+		ewarn "configure script runs into errors by default.  This causes some"
+		ewarn "configure tests to start failing, sometimes resulting in silent"
+		ewarn "breakage, missing functionality or runtime misbehavior.  It is"
+		ewarn "not yet clear whether the change will remain or be reverted."
+		ewarn
+		ewarn "For more information, please see:"
+		ewarn "https://discourse.llvm.org/t/configure-script-breakage-with-the-new-werror-implicit-function-declaration/65213"
+	fi
+}