sci-libs/flexiblas: Update the wrappers to avoid DT_AUXILIARY

Update the wrapper approach to avoid DT_AUXILIARY in the default case.
Now, libblas.so.3 & co. are symlinks to the FlexiBLAS library, so that
packages use it directly; libblas.so & co. are symlinks to wrappers
placed in a subdirectory, so they are only used to construct the correct
DT_NEEDED entries at build time.  The advantage of this approach is that
it also works on musl, so we do not have to use two different solutions.

We are still using the full library symlink tree for the wrapper
to avoid another fight with Meson, and hopefully to reduce the risk
of compatibility issues.  The library still contains DT_AUXILIARY
section, and it could still be used if one dlopens the top-level .so
file directly (rather than the .so.3).

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

sci-libs/flexiblas/flexiblas-3.4.82-r4.ebuild

@@ -0,0 +1,281 @@
+# Copyright 2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit cmake multilib toolchain-funcs
+
+MY_P=flexiblas-release-v${PV}
+DESCRIPTION="A BLAS and LAPACK wrapper library with runtime exchangable backends"
+HOMEPAGE="
+	https://www.mpi-magdeburg.mpg.de/projects/flexiblas/
+	https://gitlab.mpi-magdeburg.mpg.de/software/flexiblas-release/
+"
+SRC_URI="
+	https://gitlab.mpi-magdeburg.mpg.de/software/flexiblas-release/-/archive/v${PV}/${MY_P}.tar.bz2
+"
+S=${WORKDIR}/${MY_P}
+
+# BSD for vendored cblas/lapacke
+LICENSE="LGPL-3+ BSD"
+SLOT="0"
+KEYWORDS="~amd64 ~arm ~arm64 ~ppc ~ppc64 ~riscv ~x86"
+IUSE="blis index64 mkl openblas openmp system-blas tbb test"
+RESTRICT="!test? ( test )"
+
+# flexiblas only supports gnu-openmp using clang/gcc
+DEPEND="
+	sci-libs/lapack:=[deprecated,index64(-)?]
+	blis? ( sci-libs/blis:=[-64bit-index(-),index64(-)?] )
+	mkl? (
+		sci-libs/mkl:=[tbb?]
+		openmp? ( sci-libs/mkl[gnu-openmp] )
+	)
+	openblas? ( sci-libs/openblas:=[index64(-)?] )
+	system-blas? ( sci-libs/lapack[flexiblas(-)] )
+"
+RDEPEND="
+	${DEPEND}
+	system-blas? (
+		!app-eselect/eselect-blas
+		!app-eselect/eselect-cblas
+		!app-eselect/eselect-lapack
+		!sci-libs/lapack[-flexiblas(-)]
+		!=sci-libs/blas-lapack-aux-wrapper-0-r0
+	)
+"
+PDEPEND="
+	system-blas? (
+		>=sci-libs/blas-lapack-aux-wrapper-0-r1[index64?]
+	)
+"
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+src_prepare() {
+	local PATCHES=(
+		# extracted from
+		# https://gitlab.mpi-magdeburg.mpg.de/software/flexiblas-release/-/commit/04021ceada30f136036a22dc6c811b3d352b199d
+		"${FILESDIR}/${P}-xerbla-array.patch"
+	)
+
+	cmake_src_prepare
+
+	# remove bundled netlib blas/lapack
+	# (we still need vendored cblas/lapacke)
+	rm -r contributed/lapack-* || die
+}
+
+src_configure() {
+	BACKENDS=( $(usev blis) $(usev openblas) )
+	local extra=${BACKENDS[*]}
+	local libdir="${ESYSROOT}/usr/$(get_libdir)"
+	local mycmakeargs=(
+		-DTESTS=$(usex test)
+		-DCBLAS=ON
+		-DINTEGER8=OFF
+		-DLAPACK=ON
+		-DLINK_OPENMP=$(usex openmp)
+		-DEXAMPLES=OFF
+		# prefer OpenBLAS if available
+		-DFLEXIBLAS_DEFAULT=$(usex openblas openblas netlib)
+		# we need to enable autodetection for mkl
+		-DBLAS_AUTO_DETECT=ON
+		# ...so we need to explicitly disable autodetecting other libraries
+		# that would be pinned to their openmp/pthread/serial variants
+		-DOpenBLASSerial=OFF
+		-DOpenBLASPThread=OFF
+		-DOpenBLASOpenMP=OFF
+		-DOpenBLASSerial64=OFF
+		-DOpenBLASPThread64=OFF
+		-DOpenBLASOpenMP64=OFF
+		-DBlisSerial=OFF
+		-DBlisPThread=OFF
+		-DBlisOpenMP=OFF
+		-DBlisSerial64=OFF
+		-DBlisPThread64=OFF
+		-DBlisOpenMP64=OFF
+		# variants we use autodetection for
+		-DMklSerial=$(usex mkl ON OFF)
+		-DMklOpenMP=$(usex mkl "$(usex openmp ON OFF)" OFF)
+		-DMklTBB=$(usex mkl "$(usex tbb ON OFF)" OFF)
+		# unsupported
+		-DCMAKE_DISABLE_FIND_PACKAGE_nvpl=ON
+		-DATLAS=OFF
+		-DTATLAS=OFF
+		# and then enable our custom names via EXTRA
+		-DEXTRA="${extra// /;}"
+		# respect CFLAGS
+		-DLTO=OFF
+		# these are used only with -DEXTRA
+		-Dblis_LIBRARY="${libdir}/libblis.so"
+		-Dopenblas_LIBRARY="${libdir}/libopenblas.so"
+	)
+
+	# use system sci-libs/lapack
+	if use system-blas; then
+		# this is sci-libs/lapack[flexiblas] install
+		mycmakeargs+=(
+			-DSYS_BLAS_LIBRARY="${libdir}/libblas-reference.so"
+			-DSYS_LAPACK_LIBRARY="${libdir}/liblapack-reference.so"
+		)
+	else
+		mycmakeargs+=(
+			-DSYS_BLAS_LIBRARY="${libdir}/libblas.so"
+			-DSYS_LAPACK_LIBRARY="${libdir}/liblapack.so"
+		)
+	fi
+
+	cmake_src_configure
+
+	if use index64; then
+		mycmakeargs+=(
+			-DINTEGER8=ON
+			-Dblis_LIBRARY="${libdir}/libblis64.so"
+			-Dopenblas_LIBRARY="${libdir}/libopenblas64.so"
+		)
+
+		if use system-blas; then
+			# this is sci-libs/lapack[flexiblas] install
+			mycmakeargs+=(
+				-DSYS_BLAS_LIBRARY="${libdir}/libblas64-reference.so"
+				-DSYS_LAPACK_LIBRARY="${libdir}/liblapack64-reference.so"
+			)
+		else
+			mycmakeargs+=(
+				-DSYS_BLAS_LIBRARY="${libdir}/libblas64.so"
+				-DSYS_LAPACK_LIBRARY="${libdir}/liblapack64.so"
+			)
+		fi
+
+		BUILD_DIR=${BUILD_DIR}-ilp64 cmake_src_configure
+	fi
+
+	BACKENDS+=( netlib )
+	BACKENDS_ILP64=( "${BACKENDS[@]}" )
+	if use mkl; then
+		BACKENDS+=(
+			MklSerial
+			$(usev openmp MklOpenMP)
+			$(usev tbb MklTBB)
+		)
+		BACKENDS_ILP64+=(
+			MklSerial64
+			$(usev openmp MklOpenMP64)
+			$(usev tbb MklTBB64)
+		)
+	fi
+}
+
+src_compile() {
+	cmake_src_compile
+	use index64 && BUILD_DIR=${BUILD_DIR}-ilp64 cmake_src_compile
+}
+
+my_test() {
+	# We run tests in parallel, so avoid having n^2 threads.
+	local -x BLIS_NUM_THREADS=1
+	local -x MKL_NUM_THREADS=1
+	local -x OMP_NUM_THREADS=1
+	local -x OPENBLAS_NUM_THREADS=1
+
+	local failures=()
+	local backend
+	for backend in "${@}"; do
+		# TODO: remove this, and XFAIL them properly when cmake.eclass
+		# is fixed to respect nonfatal, https://bugs.gentoo.org/961929
+		if [[ ${backend} == Mkl* ]]; then
+			einfo "Skipping ${backend} tests, XFAIL"
+			continue
+		fi
+
+		local -x FLEXIBLAS_TEST=${backend}
+		local log=${BUILD_DIR}/Testing/Temporary/LastTest.log
+		einfo "Testing backend ${backend}"
+		if ! nonfatal cmake_src_test; then
+			failures+=( "${backend}" )
+		fi
+		if grep -q 'BLAS backend .* not found' "${log}"; then
+			die "Backend ${backend} failed to load while testing, see ${log}"
+		fi
+	done
+
+	if [[ ${failures[@]} ]]; then
+		die "Test runs failed for backends: ${failures[*]}"
+	fi
+}
+
+src_test() {
+	my_test "${BACKENDS[@]}"
+	use index64 && BUILD_DIR=${BUILD_DIR}-ilp64 my_test "${BACKENDS_ILP64[@]}"
+}
+
+verify_backends() {
+	local lib=${1}
+	shift
+	cd "${ED}/usr/$(get_libdir)/${lib}" || die
+
+	local missing=()
+	local backend
+	for backend in "${@}"; do
+		if [[ ! -f libflexiblas_${backend,,}$(get_libname) ]]; then
+			missing+=( "${backend}" )
+		fi
+	done
+
+	if [[ ${missing[@]} ]]; then
+		die "Not all requested ${lib} backends built. Missing: ${missing[*]}"
+	fi
+}
+
+src_install() {
+	cmake_src_install
+	use index64 && BUILD_DIR=${BUILD_DIR}-ilp64 cmake_src_install
+
+	# Verify built backends.
+	verify_backends flexiblas "${BACKENDS[@]}"
+	use index64 && verify_backends flexiblas64 "${BACKENDS_ILP64[@]}"
+
+	# Install symlinks for system BLAS / LAPACK use.
+	if use system-blas; then
+		local libdir="/usr/$(get_libdir)"
+		local fn suffix
+		for fn in cblas.h lapack.h lapacke{,_config,_mangling,_utils}.h; do
+			dosym "flexiblas/${fn}" "/usr/include/${fn}"
+		done
+
+		for suffix in '' $(usev index64 64); do
+			for fn in blas cblas lapack lapacke; do
+				dosym "libflexiblas${suffix}.so.3" \
+					"${libdir}/lib${fn}${suffix}.so.3"
+			done
+		done
+	fi
+}
+
+pkg_postinst() {
+	if use system-blas; then
+		# eselect-{blas,lapack} doesn't clean up its configs
+		local prev_opt=$(shopt -p nullglob)
+		shopt -s nullglob
+		local files=(
+			"${EROOT}"/etc/ld.so.conf.d/81-blas-*.conf
+			"${EROOT}"/etc/ld.so.conf.d/82-lapack-*.conf
+		)
+		${prev_opt}
+
+		if [[ ${files[@]} ]]; then
+			rm -v "${files[@]}"
+		fi
+	fi
+}

sci-libs/flexiblas/flexiblas-9999.ebuild

@@ -17,7 +17,7 @@ EGIT_REPO_URI="
 # BSD for vendored cblas/lapacke
 LICENSE="LGPL-3+ BSD"
 SLOT="0"
-IUSE="blis elibc_glibc index64 mkl openblas openmp system-blas tbb test"
+IUSE="blis index64 mkl openblas openmp system-blas tbb test"
 RESTRICT="!test? ( test )"
 
 # flexiblas only supports gnu-openmp using clang/gcc
@@ -38,13 +38,12 @@ RDEPEND="
 		!app-eselect/eselect-cblas
 		!app-eselect/eselect-lapack
 		!sci-libs/lapack[-flexiblas(-)]
+		!=sci-libs/blas-lapack-aux-wrapper-0-r0
 	)
 "
 PDEPEND="
 	system-blas? (
-		elibc_glibc? (
-			sci-libs/blas-lapack-aux-wrapper[index64?]
-		)
+		>=sci-libs/blas-lapack-aux-wrapper-0-r1[index64?]
 	)
 "
 
@@ -246,19 +245,12 @@ src_install() {
 			dosym "flexiblas/${fn}" "/usr/include/${fn}"
 		done
 
-		# On glibc, we can use sci-libs/blas-lapack-aux-wrapper.
-		if ! use elibc_glibc; then
-			for suffix in '' $(usev index64 64); do
-				for fn in blas cblas lapack lapacke; do
-					dosym "libflexiblas${suffix}.so.3" \
-						"${libdir}/lib${fn}${suffix}.so.3"
-					dosym "libflexiblas${suffix}.so" \
-						"${libdir}/lib${fn}${suffix}.so"
-					dosym "flexiblas${suffix}.pc" \
-						"${libdir}/pkgconfig/${fn}${suffix}.pc"
-				done
+		for suffix in '' $(usev index64 64); do
+			for fn in blas cblas lapack lapacke; do
+				dosym "libflexiblas${suffix}.so.3" \
+					"${libdir}/lib${fn}${suffix}.so.3"
 			done
-		fi
+		done
 	fi
 }