virtual/cblas: Add flexiblas support

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

virtual/cblas/cblas-3.8-r1.ebuild

@@ -6,12 +6,21 @@ EAPI="8"
 DESCRIPTION="Virtual for BLAS C implementation"
 SLOT="0"
 KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos"
-IUSE="eselect-ldso index64"
+IUSE="eselect-ldso flexiblas index64"
+REQUIRED_USE="?? ( eselect-ldso flexiblas )"
 
 RDEPEND="
-	>=sci-libs/lapack-3.8.0[eselect-ldso?,index64(-)?]
-	eselect-ldso? ( || (
-		>=sci-libs/lapack-3.8.0[eselect-ldso]
-		sci-libs/openblas[eselect-ldso]
-		sci-libs/blis[eselect-ldso] ) )
+	flexiblas? (
+		sci-libs/flexiblas[system-blas(-),index64(-)?]
+	)
+	!flexiblas? (
+		>=sci-libs/lapack-3.8[eselect-ldso?,-flexiblas(-),index64(-)?]
+		eselect-ldso? (
+			|| (
+				>=sci-libs/lapack-3.8[eselect-ldso]
+				sci-libs/openblas[eselect-ldso]
+				sci-libs/blis[eselect-ldso]
+			)
+		)
+	)
 "

virtual/cblas/metadata.xml

@@ -7,6 +7,7 @@
 	</maintainer>
 	<use>
 		<flag name="eselect-ldso">Enable runtime library switching by eselect and ld.so.</flag>
+		<flag name="flexiblas">Use <pkg>sci-libs/flexiblas</pkg> as the provider.</flag>
 		<flag name="index64">Provide an ILP64 library in addition to LP64</flag>
 	</use>
 	<stabilize-allarches/>