xorg-3.eclass: conditionalize autotools deps on XORG_EAUTORECONF

xorg-3.eclass only calls autoreconf if XORG_EAUTORECONF is set, although
the logic got cleaned up more in fae3e3b3ee.

We therefore don't need to depend on autoconf, automake, etc unless
XORG_EAUTORECONF is set. Set AUTOTOOLS_AUTO_DEPEND from autotools.eclass
to opt-out of the auto dependencies and use the AUTOTOOLS_DEPEND variable
it sets when XORG_EAUTORECONF.

Note that libtool.eclass still adds a dep on elt-patches so we're OK
for that part (we call elibtoolize where we can).

Signed-off-by: Sam James <sam@gentoo.org>

eclass/xorg-3.eclass

@@ -58,6 +58,7 @@ fi
 : "${XORG_MULTILIB:="no"}"
 
 # we need to inherit autotools first to get the deps
+AUTOTOOLS_AUTO_DEPEND=no
 inherit autotools libtool multilib toolchain-funcs flag-o-matic \
 	${FONT_ECLASS} ${GIT_ECLASS}
 unset FONT_ECLASS GIT_ECLASS
@@ -129,9 +130,7 @@ fi
 
 # Set up autotools shared dependencies
 # Remember that all versions here MUST be stable
-EAUTORECONF_DEPEND+="
-	>=dev-build/libtool-2.2.6a
-	sys-devel/m4"
+EAUTORECONF_DEPEND+=" ${AUTOTOOLS_DEPEND}"
 if [[ ${PN} != util-macros ]] ; then
 	EAUTORECONF_DEPEND+=" >=x11-misc/util-macros-1.18"
 	# Required even by xorg-server