llvm-core/flang: Add 21.0.0_pre20250523 snapshot

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

llvm-core/flang/Manifest

@@ -1,2 +1,3 @@
+DIST llvm-project-7dc7c155251c0008d5d59b84f0c9056365740f11.tar.gz 235921149 BLAKE2B 2867e313cd25fee6975da9bf65365fa51ed8780f3f8fc95983fb6e8f5b2c38c6d7f75a386b0ec2d74bafad74472973f4e4e603a5a0754465ac2b75942b8e90c6 SHA512 f8bc383ff2a1af836357150efa5728c7df3cd862f56ffaf12b5fc56ef631f1048276ff00b89fcf4d224576fa1eda9811d971886aae0855a4d29178060eb89a49
 DIST llvm-project-aaaae99663dbb220c6c27fa9cacf93fcb8f20e7c.tar.gz 235477577 BLAKE2B 46a3b7863cdfde75045dfcab95f8c9eee21f8ce80cee700284bc174adbb4038f23bba3b15635c88c2723ed0d20e6fddcf43c92b9e540c885af48e81bfa8c82aa SHA512 bf8e7f28622f91da57698220fca592105d109c38801b5e0312f5e290bca1ae32ef393179cfe912c194dbf85ece9bd6ee63b587157b0fcd6007bbaff3324e77ed
 DIST llvm-project-fcb4bda9dcfcdb64d8b069e8416c75d7a1a62e52.tar.gz 233149231 BLAKE2B 95a7a012a1e747afcf83ace3785c8ef6a3e10f6075e59eb1c5b077cc9edae244b648f341bc0ac6a45b2afc8f7ffe130a90a741a04465523f30f8322566386703 SHA512 b46f0c90a1c56750cada24183ca382b267a2d2faa0db7d77a8bdd4e94e6303e57d565cf85447b3c0e0efdd3750efef1e10e8ce6f1fe8f1ae10ee31d25ddf3fb7

llvm-core/flang/flang-21.0.0_pre20250523.ebuild

@@ -0,0 +1,69 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit cmake llvm.org
+
+DESCRIPTION="LLVM's Fortran frontend"
+HOMEPAGE="https://flang.llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions"
+SLOT="${LLVM_MAJOR}/${LLVM_SOABI}"
+IUSE="+debug test"
+RESTRICT="!test? ( test )"
+
+DEPEND="
+	~llvm-core/clang-${PV}[debug=]
+	~llvm-core/llvm-${PV}[debug=]
+	~llvm-core/mlir-${PV}[debug=]
+"
+RDEPEND="
+	${DEPEND}
+"
+PDEPEND="
+	>=llvm-runtimes/flang-rt-${PV}:${LLVM_MAJOR}
+"
+BDEPEND="
+	test? (
+		dev-python/lit
+	)
+"
+
+LLVM_COMPONENTS=( flang cmake )
+LLVM_TEST_COMPONENTS=( clang/test/Driver mlir/test/lib )
+llvm.org_set_globals
+
+src_configure() {
+	local mycmakeargs=(
+		-DCMAKE_INSTALL_PREFIX="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}"
+
+		-DLLVM_ROOT="${ESYSROOT}/usr/lib/llvm/${LLVM_MAJOR}"
+		-DCLANG_RESOURCE_DIR="../../../clang/${LLVM_MAJOR}"
+
+		-DBUILD_SHARED_LIBS=OFF
+		-DMLIR_LINK_MLIR_DYLIB=ON
+		# flang does not feature a dylib, so do not install libraries
+		# or headers
+		-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON
+		# installed by llvm-runtimes/flang-rt
+		-DFLANG_INCLUDE_RUNTIME=OFF
+
+		# TODO: always enable to obtain reproducible tools
+		-DFLANG_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
+}