dev-python/future: Use distutils_enable_sphinx

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

dev-python/future/future-0.18.2.ebuild

@@ -17,16 +17,12 @@ KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~mips ~ppc ~ppc64 ~s390 ~sparc ~
 IUSE="doc"
 
 distutils_enable_tests pytest
+distutils_enable_sphinx docs \
+	dev-python/sphinx-bootstrap-theme
 
 # TODO: make numpy unconditional when it supports py3.8
-BDEPEND="
+BDEPEND+="
 	dev-python/setuptools[${PYTHON_USEDEP}]
-	doc? (
-		$(python_gen_any_dep '
-			dev-python/sphinx[${PYTHON_USEDEP}]
-			dev-python/sphinx-bootstrap-theme[${PYTHON_USEDEP}]
-		')
-	)
 	test? (
 		$(python_gen_cond_dep 'dev-python/numpy[${PYTHON_USEDEP}]' \
 			python{2_7,3_{5,6,7}})
@@ -37,12 +33,6 @@ PATCHES=(
 	"${FILESDIR}"/${P}-tests.patch
 )
 
-python_check_deps() {
-	use doc || return 0
-	has_version "dev-python/sphinx[${PYTHON_USEDEP}]" &&
-		has_version "dev-python/sphinx-bootstrap-theme[${PYTHON_USEDEP}]"
-}
-
 python_prepare_all() {
 	sed -i "/'sphinx.ext.intersphinx'/d" docs/conf.py || die
 	# tests requiring network access
@@ -52,10 +42,3 @@ python_prepare_all() {
 
 	distutils-r1_python_prepare_all
 }
-
-python_compile_all() {
-	if use doc; then
-		sphinx-build docs/ docs/_build/html || die
-		HTML_DOCS=( docs/_build/html/. )
-	fi
-}