sci-mathematics/frama-c: split plugins from main ebuild

USE flags are not meant for this (causing recompilation of everything
when changing plugins configuration). In addition, this solves the
problem of the main frama-c ebuild having too much USE flags.

Signed-off-by: François-Xavier Carton <fx.carton91@gmail.com>

sci-mathematics/frama-c-loopanalysis/frama-c-loopanalysis-23.1.ebuild

@@ -0,0 +1,42 @@
+# Copyright 1999-2021 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit autotools findlib toolchain-funcs
+
+DESCRIPTION="Loop analysis plugin for frama-c"
+HOMEPAGE="https://frama-c.com"
+NAME="Vanadium"
+SRC_URI="https://frama-c.com/download/frama-c-${PV}-${NAME}.tar.gz"
+
+LICENSE="LGPL-2.1"
+SLOT="0"
+KEYWORDS="~amd64"
+IUSE="+ocamlopt"
+RESTRICT="strip"
+
+RDEPEND="~sci-mathematics/frama-c-${PV}:=[ocamlopt?]"
+DEPEND="${RDEPEND}"
+
+S="${WORKDIR}/frama-c-${PV}-${NAME}/src/plugins/loop_analysis"
+
+src_prepare() {
+	export FRAMAC_SHARE="${ESYSROOT}/usr/share/frama-c"
+	export FRAMAC_LIBDIR="${EPREFIX}/usr/$(get_libdir)/frama-c"
+	eautoconf
+	eapply_user
+}
+
+src_configure() {
+	econf --enable-loop-analysis
+}
+
+src_compile() {
+	tc-export AR
+	emake FRAMAC_SHARE="${FRAMAC_SHARE}" FRAMAC_LIBDIR="${FRAMAC_LIBDIR}"
+}
+
+src_install() {
+	emake FRAMAC_SHARE="${FRAMAC_SHARE}" FRAMAC_LIBDIR="${FRAMAC_LIBDIR}" DESTDIR="${ED}" install
+}