llvm-runtimes/flang-rt: Add 21.0.0_pre20250420 snapshot

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

llvm-runtimes/flang-rt/Manifest

@@ -1 +1,2 @@
 DIST llvm-project-1cf9f764ac41fb3492e10c78640dd50e616388db.tar.gz 230651433 BLAKE2B b71d459de99a741f9eb5809fcb44e6d9a17d3295bf11755d2b04a83fff6257eb4e5856826581c000e3b2868ff1cfb155ee18c692654f8083af04574d414c8fa2 SHA512 5b8d1e493830b7838b3ca76148dfc2e2af1cbaa660bd80958777698210c3347a1308f0725d40b10f8f12877daf99c4ba4837e4fa857a781ae912ee167369bafd
+DIST llvm-project-ac8fc09688e10e983b99224b5dc5cbbeeedb1879.tar.gz 231567089 BLAKE2B f7878f114c908b21d179854bc693716b34b963612c6b5172789a37cd21fa316720d4e9498bc7679058db3e822ed240bfdafd85bfd00154914d747d0c0ed1cb48 SHA512 4c39db8b22fa087ca96c3b4541ec77ba8a826a126b4e93b0650e59b3622b22b329f60fa3780dd4572fdece409fd5833eda473046d7547f6ee3ac8aadb8f2fc34

llvm-runtimes/flang-rt/flang-rt-21.0.0_pre20250420.ebuild

@@ -0,0 +1,64 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit cmake flag-o-matic llvm.org
+
+DESCRIPTION="LLVM's Fortran runtime"
+HOMEPAGE="https://flang.llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions"
+SLOT="${LLVM_MAJOR}"
+IUSE="+debug test"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+	!<llvm-core/flang-21.0.0_pre20250221-r1
+"
+BDEPEND="
+	llvm-core/llvm:${LLVM_MAJOR}
+	llvm-core/flang
+	test? (
+		dev-python/lit
+	)
+"
+
+LLVM_COMPONENTS=(
+	runtimes flang-rt cmake flang llvm/{cmake,utils/llvm-lit}
+)
+llvm.org_set_globals
+
+src_configure() {
+	# the code is not portable
+	local -x FC=flang F77=flang
+	strip-unsupported-flags
+
+	local mycmakeargs=(
+		# we may not have a runtime yet
+		-DCMAKE_Fortran_COMPILER_WORKS=TRUE
+
+		-DLLVM_ENABLE_RUNTIMES="flang-rt"
+		# this package forces NO_DEFAULT_PATHS
+		-DLLVM_BINARY_DIR="${ESYSROOT}/usr/lib/llvm/${LLVM_MAJOR}"
+		# set correct install paths
+		-DFLANG_RT_INSTALL_RESOURCE_PATH="/usr/lib/clang/${LLVM_MAJOR}"
+		-DLLVM_DEFAULT_TARGET_TRIPLE="${CHOST}"
+
+		-DFLANG_RT_INCLUDE_TESTS=$(usex test)
+	)
+	use test && mycmakeargs+=(
+		-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+		-DLLVM_LIT_ARGS="$(get_lit_flags)"
+	)
+
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+	cmake_build check-flang-rt
+}